From db1d22df7f511ce504ee042092877723e46aad28 Mon Sep 17 00:00:00 2001
From: Andrey Tkachenko <andrey@aidev.ru>
Date: Tue, 22 Jun 2021 18:43:06 +0400
Subject: [PATCH] Request/Response

---
 Cargo.toml                              |   5 +-
 examples/demo.rs                        |  79 -------
 examples/demo_async.rs                  |   6 +-
 examples/demo_backpressure.rs           |  13 +-
 examples/demo_req_resp.rs               | 172 +++++++++++++++
 src/builder.rs                          |  36 ++--
 src/handler.rs                          |   1 -
 src/lib.rs                              | 129 +++++++----
 src/receiver.rs                         | 273 +++++++++++++++---------
 src/receivers/buffer_unordered/async.rs | 143 +++++++------
 src/receivers/buffer_unordered/sync.rs  | 145 +++++++------
 src/receivers/mod.rs                    |   9 +-
 12 files changed, 639 insertions(+), 372 deletions(-)
 delete mode 100644 examples/demo.rs
 create mode 100644 examples/demo_req_resp.rs

diff --git a/Cargo.toml b/Cargo.toml
index 1fdc18b..4448f39 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,17 +11,16 @@ exclude = [".gitignore", ".cargo/config", ".github/**", "codecov.yml"]
 edition = "2018"
 
 [dependencies]
-tokio = { version = "1", features = ["parking_lot", "rt-multi-thread", "io-util", "sync"] }
+tokio = { version = "1", features = ["parking_lot", "rt-multi-thread", "sync"] }
 parking_lot = "0.11.1"
 async-trait = "0.1.42"
 futures = "0.3.8"
 anyhow = "1.0.34"
-crossbeam = "0.8.1"
-uuid = "0.8.2"
 tokio-util = "0.6.7"
 async-stream = "0.3.2"
 smallvec = "1.6.1"
 log = "0.4.14"
+sharded-slab = "0.1.1"
 
 [dev-dependencies]
 tokio = { version = "1", features = ["macros", "parking_lot", "rt-multi-thread", "io-util", "sync"] }
diff --git a/examples/demo.rs b/examples/demo.rs
deleted file mode 100644
index c83d523..0000000
--- a/examples/demo.rs
+++ /dev/null
@@ -1,79 +0,0 @@
-use messagebus::{receivers, Bus, Handler, Result as MbusResult};
-
-struct TmpReceiver;
-struct TmpReceiver2;
-
-impl Handler<f32> for TmpReceiver {
-    fn handle(&self, msg: f32, bus: &Bus) -> MbusResult {
-        bus.try_send(1u16).unwrap();
-
-        println!("---> f32 {}", msg);
-        Ok(())
-    }
-}
-
-impl Handler<u16> for TmpReceiver {
-    fn handle(&self, msg: u16, bus: &Bus) -> MbusResult {
-        bus.try_send(1u32).unwrap();
-        println!("---> u16 {}", msg);
-        Ok(())
-    }
-}
-
-impl Handler<u32> for TmpReceiver {
-    fn handle(&self, msg: u32, bus: &Bus) -> MbusResult {
-        bus.try_send(2i32).unwrap();
-        println!("---> u32 {}", msg);
-        Ok(())
-    }
-}
-
-impl Handler<i32> for TmpReceiver {
-    fn handle(&self, msg: i32, bus: &Bus) -> MbusResult {
-        bus.try_send(3i16).unwrap();
-        println!("---> i32 {}", msg);
-        Ok(())
-    }
-}
-
-impl Handler<i16> for TmpReceiver {
-    fn handle(&self, msg: i16, _bus: &Bus) -> MbusResult {
-        println!("---> i16 {}", msg);
-        Ok(())
-    }
-}
-
-impl Handler<i32> for TmpReceiver2 {
-    fn handle(&self, msg: i32, bus: &Bus) -> MbusResult {
-        bus.try_send(3i16).unwrap();
-        println!("---> 2 i32 {}", msg);
-        Ok(())
-    }
-}
-
-impl Handler<i16> for TmpReceiver2 {
-    fn handle(&self, msg: i16, _bus: &Bus) -> MbusResult {
-        println!("---> 2 i16 {}", msg);
-        Ok(())
-    }
-}
-
-#[tokio::main]
-async fn main() {
-    let (b, poller) = Bus::build()
-        .register(TmpReceiver)
-        .subscribe::<f32, receivers::BufferUnorderedSync<_>>(Default::default())
-        .subscribe::<u16, receivers::BufferUnorderedSync<_>>(Default::default())
-        .subscribe::<u32, receivers::BufferUnorderedSync<_>>(Default::default())
-        .subscribe::<i32, receivers::BufferUnorderedSync<_>>(Default::default())
-        .subscribe::<i16, receivers::BufferUnorderedSync<_>>(Default::default())
-        .done()
-        .register(TmpReceiver2)
-        .subscribe::<i32, receivers::BufferUnorderedSync<_>>(Default::default())
-        .subscribe::<i16, receivers::BufferUnorderedSync<_>>(Default::default())
-        .done()
-        .build();
-
-    b.send(32f32).await.unwrap();
-    poller.await
-}
diff --git a/examples/demo_async.rs b/examples/demo_async.rs
index dcbd72c..a480210 100644
--- a/examples/demo_async.rs
+++ b/examples/demo_async.rs
@@ -144,10 +144,10 @@ async fn main() {
         .subscribe::<i16, receivers::BufferUnorderedAsync<_>, _, _>(8, Default::default())
         .done()
         .register(TmpReceiver2)
-            .subscribe::<i32, receivers::BufferUnorderedAsync<_>, _, _>(8, Default::default())
-            .subscribe::<i16, receivers::BufferUnorderedSync<_>, _, _>(8, Default::default())
+        .subscribe::<i32, receivers::BufferUnorderedAsync<_>, _, _>(8, Default::default())
+        .subscribe::<i16, receivers::BufferUnorderedSync<_>, _, _>(8, Default::default())
         .done()
-    .build();
+        .build();
 
     b.send(0f32).await.unwrap();
 
diff --git a/examples/demo_backpressure.rs b/examples/demo_backpressure.rs
index 7c21799..7b041e0 100644
--- a/examples/demo_backpressure.rs
+++ b/examples/demo_backpressure.rs
@@ -1,5 +1,5 @@
 use async_trait::async_trait;
-use messagebus::{receivers, Bus, AsyncHandler};
+use messagebus::{receivers, AsyncHandler, Bus};
 
 struct TmpReceiver;
 
@@ -22,10 +22,13 @@ impl AsyncHandler<f32> for TmpReceiver {
 async fn main() {
     let (b, poller) = Bus::build()
         .register(TmpReceiver)
-        .subscribe::<f32, receivers::BufferUnorderedAsync<_>, _, _>(1, receivers::BufferUnorderedConfig {
-            buffer_size: 1,
-            max_parallel: 1,
-        })
+        .subscribe::<f32, receivers::BufferUnorderedAsync<_>, _, _>(
+            1,
+            receivers::BufferUnorderedConfig {
+                buffer_size: 1,
+                max_parallel: 1,
+            },
+        )
         .done()
         .build();
 
diff --git a/examples/demo_req_resp.rs b/examples/demo_req_resp.rs
new file mode 100644
index 0000000..8cabfed
--- /dev/null
+++ b/examples/demo_req_resp.rs
@@ -0,0 +1,172 @@
+use async_trait::async_trait;
+use messagebus::{receivers, AsyncHandler, Bus};
+
+struct TmpReceiver1;
+struct TmpReceiver2;
+
+#[async_trait]
+impl AsyncHandler<i32> for TmpReceiver1 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: i32, bus: &Bus) -> Result<Self::Response, Self::Error> {
+        let resp1 = bus.request::<_, f32>(10i16, Default::default()).await?;
+        let resp2 = bus.request::<_, f32>(20u16, Default::default()).await?;
+
+        Ok(msg as f32 + resp1 + resp2)
+    }
+
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver1 i32: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<u32> for TmpReceiver1 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: u32, _bus: &Bus) -> Result<Self::Response, Self::Error> {
+        Ok(msg as f32)
+    }
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver1 u32: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<i16> for TmpReceiver1 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: i16, bus: &Bus) -> Result<Self::Response, Self::Error> {
+        let resp1 = bus.request::<_, f32>(1i8, Default::default()).await?;
+        let resp2 = bus.request::<_, f32>(2u8, Default::default()).await?;
+
+        Ok(msg as f32 + resp1 + resp2)
+    }
+
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver i16: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<u16> for TmpReceiver1 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: u16, _bus: &Bus) -> Result<Self::Response, Self::Error> {
+        Ok(msg as f32)
+    }
+
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver i16: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<i8> for TmpReceiver1 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: i8, _bus: &Bus) -> Result<Self::Response, Self::Error> {
+        Ok(msg as f32)
+    }
+
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver1 i8: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<u8> for TmpReceiver1 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: u8, _bus: &Bus) -> Result<Self::Response, Self::Error> {
+        Ok(msg as f32)
+    }
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver1 u8: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<f64> for TmpReceiver2 {
+    type Error = anyhow::Error;
+    type Response = f64;
+
+    async fn handle(&self, msg: f64, bus: &Bus) -> Result<Self::Response, Self::Error> {
+        let resp1 = bus.request::<_, f32>(100i32, Default::default()).await? as f64;
+        let resp2 = bus.request::<_, f32>(200u32, Default::default()).await? as f64;
+        let resp3 = bus.request::<_, f32>(300f32, Default::default()).await? as f64;
+
+        Ok(msg + resp1 + resp2 + resp3)
+    }
+
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver1 f64: sync");
+
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl AsyncHandler<f32> for TmpReceiver2 {
+    type Error = anyhow::Error;
+    type Response = f32;
+
+    async fn handle(&self, msg: f32, _bus: &Bus) -> Result<Self::Response, Self::Error> {
+        Ok(msg)
+    }
+    async fn sync(&self, _bus: &Bus) -> Result<(), Self::Error> {
+        println!("TmpReceiver2: f32: sync");
+
+        Ok(())
+    }
+}
+
+#[tokio::main]
+async fn main() {
+    let (b, poller) = Bus::build()
+        .register(TmpReceiver1)
+        .subscribe::<i32, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .subscribe::<u32, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .subscribe::<i16, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .subscribe::<u16, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .subscribe::<i8, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .subscribe::<u8, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .done()
+        .register(TmpReceiver2)
+        .subscribe::<f32, receivers::BufferUnorderedAsync<_, f32>, _, _>(8, Default::default())
+        .subscribe::<f64, receivers::BufferUnorderedAsync<_, f64>, _, _>(8, Default::default())
+        .done()
+        .build();
+
+    println!(
+        "{:?}",
+        b.request::<_, f64>(1000f64, Default::default()).await
+    );
+
+    println!("flush");
+    b.flush().await;
+
+    println!("close");
+    b.close().await;
+
+    poller.await;
+    println!("[done]");
+}
diff --git a/src/builder.rs b/src/builder.rs
index a15d1c5..0af7a5b 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -3,19 +3,31 @@ use std::{any::TypeId, collections::HashMap, marker::PhantomData, pin::Pin, sync
 use futures::{Future, FutureExt};
 use tokio::sync::Mutex;
 
-use crate::{Bus, BusInner, Message, Untyped, receiver::{Receiver, ReciveTypedReceiver, SendTypedReceiver, SendUntypedReceiver}};
+use crate::{
+    receiver::{Receiver, ReciveTypedReceiver, SendTypedReceiver, SendUntypedReceiver},
+    Bus, BusInner, Message, Untyped,
+};
 
-
-pub trait ReceiverSubscriberBuilder<T, M, R, E>: SendUntypedReceiver + SendTypedReceiver<M> + ReciveTypedReceiver<R, E>
-    where
-        T: 'static,
-        M: Message,
-        R: Message,
-        E: crate::Error
+pub trait ReceiverSubscriberBuilder<T, M, R, E>:
+    SendUntypedReceiver + SendTypedReceiver<M> + ReciveTypedReceiver<R, E>
+where
+    T: 'static,
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     type Config: Default;
 
-    fn build(cfg: Self::Config) -> (Self, Box<dyn FnOnce(Untyped) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>>) where Self: Sized;
+    fn build(
+        cfg: Self::Config,
+    ) -> (
+        Self,
+        Box<
+            dyn FnOnce(Untyped) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>,
+        >,
+    )
+    where
+        Self: Sized;
 }
 
 pub struct SyncEntry;
@@ -35,7 +47,7 @@ pub struct RegisterEntry<K, T> {
                 )
                     -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>,
             >,
-            Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>
+            Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>,
         )>,
     >,
     _m: PhantomData<(K, T)>,
@@ -68,7 +80,7 @@ impl<T> RegisterEntry<UnsyncEntry, T> {
     {
         let (inner, poller) = S::build(cfg);
 
-        let receiver = Receiver::new(queue, inner);
+        let receiver = Receiver::new::<M, R, E, S>(queue, inner);
         let poller2 = receiver.start_polling_events::<R, E>();
         self.receivers
             .entry(TypeId::of::<M>())
@@ -90,7 +102,7 @@ impl<T> RegisterEntry<SyncEntry, T> {
     {
         let (inner, poller) = S::build(cfg);
 
-        let receiver = Receiver::new(queue, inner);
+        let receiver = Receiver::new::<M, R, E, S>(queue, inner);
         let poller2 = receiver.start_polling_events::<R, E>();
         self.receivers
             .entry(TypeId::of::<M>())
diff --git a/src/handler.rs b/src/handler.rs
index 26b15ec..09d1353 100644
--- a/src/handler.rs
+++ b/src/handler.rs
@@ -106,7 +106,6 @@ pub trait LocalAsyncHandler<M: Message> {
     }
 }
 
-
 pub trait LocalBatchHandler<M: Message> {
     type Error: crate::Error;
     type Response: Message;
diff --git a/src/lib.rs b/src/lib.rs
index a1b241a..96009a8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,24 +9,30 @@ mod trait_object;
 #[macro_use]
 extern crate log;
 
+use anyhow::bail;
 use builder::BusBuilder;
 pub use envelop::Message;
-use futures::{Future, FutureExt, future::poll_fn};
 pub use handler::*;
 pub use receiver::SendError;
 use receiver::{Receiver, ReceiverStats};
 use smallvec::SmallVec;
-use tokio::sync::{mpsc, oneshot};
+use tokio::sync::oneshot;
 
-use core::any::{Any, TypeId};
-use std::{collections::HashMap, sync::{Arc, atomic::{AtomicBool, AtomicU64, Ordering}}};
 use crate::receiver::Permit;
+use core::any::{Any, TypeId};
+use std::{
+    collections::HashMap,
+    sync::{
+        atomic::{AtomicBool, AtomicU64, Ordering},
+        Arc,
+    },
+};
 
 pub type Untyped = Arc<dyn Any + Send + Sync>;
 
 // pub trait ErrorTrait: std::error::Error + Send + Sync + 'static {}
 pub trait Error: Into<anyhow::Error> + Send + Sync + 'static {}
-impl <T: Into<anyhow::Error> + Send + Sync + 'static> Error for T {}
+impl<T: Into<anyhow::Error> + Send + Sync + 'static> Error for T {}
 
 static ID_COUNTER: AtomicU64 = AtomicU64::new(1);
 
@@ -54,7 +60,8 @@ impl BusInner {
         let mut receivers = HashMap::new();
 
         for (key, value) in input {
-            receivers.entry(key)
+            receivers
+                .entry(key)
                 .or_insert_with(SmallVec::new)
                 .push(value);
         }
@@ -83,10 +90,9 @@ impl BusInner {
             iters += 1;
             let mut flushed = false;
             for (_, rs) in &self.receivers {
-                
                 for r in rs {
                     if r.need_flush() {
-                        flushed = true; 
+                        flushed = true;
                         r.flush().await;
                     }
                 }
@@ -99,11 +105,14 @@ impl BusInner {
         }
 
         if !breaked {
-            warn!("!!! WARNING: unable to reach equilibrium in {} iterations !!!", fuse_count);
+            warn!(
+                "!!! WARNING: unable to reach equilibrium in {} iterations !!!",
+                fuse_count
+            );
         } else {
             info!("flushed in {} iterations !!!", iters);
         }
-    } 
+    }
 
     pub async fn flash_and_sync(&self) {
         self.flush().await;
@@ -122,7 +131,7 @@ impl BusInner {
     //         .map(|r| r.stats())
     // }
 
-    fn try_reserve(&self, rs: &[Receiver]) -> Option<SmallVec::<[Permit; 32]>> {
+    fn try_reserve(&self, rs: &[Receiver]) -> Option<SmallVec<[Permit; 32]>> {
         let mut permits = SmallVec::<[Permit; 32]>::new();
 
         for r in rs {
@@ -135,13 +144,17 @@ impl BusInner {
 
         Some(permits)
     }
- 
+
     #[inline]
     pub fn try_send<M: Message>(&self, msg: M) -> core::result::Result<(), SendError<M>> {
         self.try_send_ext(msg, SendOptions::Broadcast)
     }
 
-    pub fn try_send_ext<M: Message>(&self, msg: M, _options: SendOptions) -> core::result::Result<(), SendError<M>> {
+    pub fn try_send_ext<M: Message>(
+        &self,
+        msg: M,
+        _options: SendOptions,
+    ) -> core::result::Result<(), SendError<M>> {
         if self.closed.load(Ordering::SeqCst) {
             warn!("Bus closed. Skipping send!");
             return Ok(());
@@ -174,7 +187,10 @@ impl BusInner {
             }
         }
 
-        warn!("Unhandled message {:?}: no receivers", core::any::type_name::<M>());
+        warn!(
+            "Unhandled message {:?}: no receivers",
+            core::any::type_name::<M>()
+        );
 
         Ok(())
     }
@@ -185,16 +201,24 @@ impl BusInner {
     }
 
     #[inline]
-    pub fn send_blocking_ext<M: Message>(&self, msg: M, options: SendOptions) -> core::result::Result<(), SendError<M>> {
+    pub fn send_blocking_ext<M: Message>(
+        &self,
+        msg: M,
+        options: SendOptions,
+    ) -> core::result::Result<(), SendError<M>> {
         futures::executor::block_on(self.send_ext(msg, options))
     }
 
     #[inline]
-    pub async fn send<M: Message>(&self, msg: M, ) -> core::result::Result<(), SendError<M>> {
+    pub async fn send<M: Message>(&self, msg: M) -> core::result::Result<(), SendError<M>> {
         self.send_ext(msg, SendOptions::Broadcast).await
     }
 
-    pub async fn send_ext<M: Message>(&self, msg: M, _options: SendOptions) -> core::result::Result<(), SendError<M>> {
+    pub async fn send_ext<M: Message>(
+        &self,
+        msg: M,
+        _options: SendOptions,
+    ) -> core::result::Result<(), SendError<M>> {
         if self.closed.load(Ordering::SeqCst) {
             return Err(SendError::Closed(msg));
         }
@@ -214,7 +238,10 @@ impl BusInner {
             }
         }
 
-        warn!("Unhandled message {:?}: no receivers", core::any::type_name::<M>());
+        warn!(
+            "Unhandled message {:?}: no receivers",
+            core::any::type_name::<M>()
+        );
 
         Ok(())
     }
@@ -224,7 +251,11 @@ impl BusInner {
         self.force_send_ext(msg, SendOptions::Broadcast)
     }
 
-    pub fn force_send_ext<M: Message>(&self, msg: M, _options: SendOptions) -> core::result::Result<(), SendError<M>> {
+    pub fn force_send_ext<M: Message>(
+        &self,
+        msg: M,
+        _options: SendOptions,
+    ) -> core::result::Result<(), SendError<M>> {
         if self.closed.load(Ordering::SeqCst) {
             return Err(SendError::Closed(msg));
         }
@@ -244,32 +275,56 @@ impl BusInner {
             }
         }
 
-        warn!("Unhandled message {:?}: no receivers", core::any::type_name::<M>());
+        warn!(
+            "Unhandled message {:?}: no receivers",
+            core::any::type_name::<M>()
+        );
 
         Ok(())
     }
 
-    // pub fn request<M: Message, R: Message>(&self, req: M, options: SendOptions) -> impl Future<Output = anyhow::Result<R>> {
-    //     let mid = ID_COUNTER.fetch_add(1, Ordering::Relaxed);
-    //     let tid = TypeId::of::<M>();
-    //     let rid = TypeId::of::<R>();
+    pub async fn request<M: Message, R: Message>(
+        &self,
+        req: M,
+        options: SendOptions,
+    ) -> anyhow::Result<R> {
+        let tid = TypeId::of::<M>();
+        let rid = TypeId::of::<R>();
 
-    //     let mut iter = self.select_receivers(options, Some(rid));
-    //     let first = iter.next();
+        let mut iter = self.select_receivers(tid, options, Some(rid));
+        if let Some(rc) = iter.next() {
+            let (tx, rx) = oneshot::channel();
+            let mid = (rc.add_response_waiter(tx).unwrap() | 1 << (usize::BITS - 1)) as u64;
+            rc.send(mid, rc.reserve().await, req)?;
 
-    //     for rs in iter {
-    //         let _ = rs.send(mid, rs.reserve().await, req.clone());
-    //     }
-        
-    //     first.send(mid, first.reserve().await, req);
+            Ok(rx.await?)
+        } else {
+            bail!("No Receivers!");
+        }
+    }
 
-    //     let (tx, rx) = tokio::sync::oneshot::channel();
-    //     self.response_waiters.insert(mid, tx);
+    #[inline]
+    fn select_receivers(
+        &self,
+        tid: TypeId,
+        _options: SendOptions,
+        rid: Option<TypeId>,
+    ) -> impl Iterator<Item = &Receiver> + '_ {
+        self.receivers
+            .get(&tid)
+            .into_iter()
+            .map(|item| item.iter())
+            .flatten()
+            .filter(move |x| {
+                let ret_ty = if let Some(rid) = rid {
+                    x.resp_type_id() == rid
+                } else {
+                    true
+                };
 
-    //     poll_fn(move |cx| {
-    //         rx.poll_unpin(cx)
-    //     })
-    // }
+                ret_ty
+            })
+    }
 }
 
 #[derive(Clone)]
diff --git a/src/receiver.rs b/src/receiver.rs
index 1b3f072..27191a3 100644
--- a/src/receiver.rs
+++ b/src/receiver.rs
@@ -1,10 +1,30 @@
-use crate::{Bus, Error, Message, msgs, trait_object::TraitObject};
-use core::{any::TypeId, fmt, marker::PhantomData, mem, pin::Pin, task::{Context, Poll}};
+use crate::{msgs, trait_object::TraitObject, Bus, Error, Message};
+use core::{
+    any::TypeId,
+    fmt,
+    marker::PhantomData,
+    mem,
+    pin::Pin,
+    task::{Context, Poll},
+};
 use futures::future::poll_fn;
-use tokio::sync::Notify;
-use std::{borrow::Cow, sync::{Arc, atomic::{AtomicBool, AtomicU64, Ordering}}};
 use futures::Future;
+use std::{
+    any::Any,
+    borrow::Cow,
+    sync::{
+        atomic::{AtomicBool, AtomicU64, Ordering},
+        Arc,
+    },
+};
+use tokio::sync::{oneshot, Notify};
 
+struct SlabCfg;
+impl sharded_slab::Config for SlabCfg {
+    const RESERVED_BITS: usize = 1;
+}
+
+type Slab<T> = sharded_slab::Slab<T, SlabCfg>;
 
 pub trait SendUntypedReceiver: Send + Sync {
     fn send(&self, msg: Action) -> Result<(), SendError<Action>>;
@@ -14,9 +34,10 @@ pub trait SendTypedReceiver<M: Message>: Sync {
     fn send(&self, mid: u64, msg: M) -> Result<(), SendError<M>>;
 }
 
-pub trait ReciveTypedReceiver<M, E>: Sync 
-    where M: Message,
-          E: crate::Error
+pub trait ReciveTypedReceiver<M, E>: Sync
+where
+    M: Message,
+    E: crate::Error,
 {
     fn poll_events(&self, ctx: &mut Context<'_>) -> Poll<Event<M, E>>;
 }
@@ -24,7 +45,6 @@ pub trait ReciveTypedReceiver<M, E>: Sync
 pub trait ReceiverTrait: Send + Sync {
     fn typed(&self) -> AnyReceiver<'_>;
     fn poller(&self) -> AnyPoller<'_>;
-    fn type_id(&self) -> TypeId;
     fn stats(&self) -> Result<(), SendError<()>>;
     fn close(&self) -> Result<(), SendError<()>>;
     fn sync(&self) -> Result<(), SendError<()>>;
@@ -39,7 +59,6 @@ pub trait PermitDrop {
     fn permit_drop(&self);
 }
 
-
 #[derive(Debug, Clone)]
 pub struct Stats {
     pub has_queue: bool,
@@ -75,20 +94,22 @@ pub enum Event<M, E> {
 }
 
 struct ReceiverWrapper<M, R, E, S>
-    where M: Message,
-          R: Message,
-          E: Error,
-          S: 'static
-{ 
-    inner: S, 
-    _m: PhantomData<(M, R, E)> 
+where
+    M: Message,
+    R: Message,
+    E: Error,
+    S: 'static,
+{
+    inner: S,
+    _m: PhantomData<(M, R, E)>,
 }
 
-impl<M, R, E, S> ReceiverTrait for ReceiverWrapper<M, R, E, S> 
-    where M: Message,
-          R: Message,
-          E: Error,
-          S: SendUntypedReceiver + SendTypedReceiver<M> + ReciveTypedReceiver<R, E> + 'static
+impl<M, R, E, S> ReceiverTrait for ReceiverWrapper<M, R, E, S>
+where
+    M: Message,
+    R: Message,
+    E: Error,
+    S: SendUntypedReceiver + SendTypedReceiver<M> + ReciveTypedReceiver<R, E> + 'static,
 {
     fn typed(&self) -> AnyReceiver<'_> {
         AnyReceiver::new(&self.inner)
@@ -98,30 +119,26 @@ impl<M, R, E, S> ReceiverTrait for ReceiverWrapper<M, R, E, S>
         AnyPoller::new(&self.inner)
     }
 
-    fn type_id(&self) -> TypeId {
-        TypeId::of::<S>()
-    }
-
     fn stats(&self) -> Result<(), SendError<()>> {
-        SendUntypedReceiver::send(&self.inner, Action::Stats).map_err(|_|SendError::Closed(()))
+        SendUntypedReceiver::send(&self.inner, Action::Stats).map_err(|_| SendError::Closed(()))
     }
 
     fn close(&self) -> Result<(), SendError<()>> {
-        SendUntypedReceiver::send(&self.inner, Action::Close).map_err(|_|SendError::Closed(()))
+        SendUntypedReceiver::send(&self.inner, Action::Close).map_err(|_| SendError::Closed(()))
     }
 
     fn sync(&self) -> Result<(), SendError<()>> {
-        SendUntypedReceiver::send(&self.inner, Action::Sync).map_err(|_|SendError::Closed(()))
+        SendUntypedReceiver::send(&self.inner, Action::Sync).map_err(|_| SendError::Closed(()))
     }
 
     fn flush(&self) -> Result<(), SendError<()>> {
-        SendUntypedReceiver::send(&self.inner, Action::Flush).map_err(|_|SendError::Closed(()))
+        SendUntypedReceiver::send(&self.inner, Action::Flush).map_err(|_| SendError::Closed(()))
     }
 }
 
 pub struct Permit {
     pub(crate) fuse: bool,
-    pub(crate) inner: Arc<dyn PermitDrop>
+    pub(crate) inner: Arc<dyn PermitDrop>,
 }
 
 impl Drop for Permit {
@@ -167,11 +184,11 @@ pub struct AnyPoller<'a> {
 unsafe impl Send for AnyPoller<'_> {}
 
 impl<'a> AnyPoller<'a> {
-    pub fn new<M, E, R>(rcvr: &'a R) -> Self 
-        where 
-            M: Message,
-            E: crate::Error,
-            R: ReciveTypedReceiver<M, E> + 'static
+    pub fn new<M, E, R>(rcvr: &'a R) -> Self
+    where
+        M: Message,
+        E: crate::Error,
+        R: ReciveTypedReceiver<M, E> + 'static,
     {
         let trcvr = rcvr as &(dyn ReciveTypedReceiver<M, E>);
 
@@ -182,7 +199,9 @@ impl<'a> AnyPoller<'a> {
         }
     }
 
-    pub fn dyn_typed_receiver<M: Message, E: crate::Error>(&'a self) -> &'a dyn ReciveTypedReceiver<M, E> {
+    pub fn dyn_typed_receiver<M: Message, E: crate::Error>(
+        &'a self,
+    ) -> &'a dyn ReciveTypedReceiver<M, E> {
         assert_eq!(self.type_id, TypeId::of::<dyn ReciveTypedReceiver<M, E>>());
 
         unsafe { mem::transmute(self.dyn_typed_receiver_trait_object) }
@@ -242,6 +261,7 @@ impl fmt::Display for ReceiverStats {
 }
 
 struct ReceiverContext {
+    resp_type_id: TypeId,
     limit: u64,
     processing: AtomicU64,
     need_flush: AtomicBool,
@@ -261,6 +281,7 @@ impl PermitDrop for ReceiverContext {
 pub struct Receiver {
     inner: Arc<dyn ReceiverTrait>,
     context: Arc<ReceiverContext>,
+    waiters: Arc<dyn Any + Send + Sync>,
 }
 
 impl fmt::Debug for Receiver {
@@ -280,32 +301,38 @@ impl core::cmp::Eq for Receiver {}
 
 impl Receiver {
     #[inline]
-    pub(crate) fn new<M, R, E, S>(limit: u64, inner: S) -> Self 
-    where M: Message,
-          R: Message,
-          E: Error,
-          S: SendUntypedReceiver + SendTypedReceiver<M> + ReciveTypedReceiver<R, E> + 'static
+    pub(crate) fn new<M, R, E, S>(limit: u64, inner: S) -> Self
+    where
+        M: Message,
+        R: Message,
+        E: Error,
+        S: SendUntypedReceiver + SendTypedReceiver<M> + ReciveTypedReceiver<R, E> + 'static,
     {
-        let context = Arc::new(ReceiverContext {
-            limit,
-            processing: AtomicU64::new(0),
-            need_flush: AtomicBool::new(false),
-            flushed: Notify::new(),
-            synchronized: Notify::new(),
-            closed: Notify::new(),
-            response: Notify::new(),
-            statistics: Notify::new(),
-        });
-
-        Self { inner: Arc::new(ReceiverWrapper{
-            inner,
-            _m: Default::default()
-        }), context }
+        Self {
+            context: Arc::new(ReceiverContext {
+                resp_type_id: TypeId::of::<R>(),
+                limit,
+                processing: AtomicU64::new(0),
+                need_flush: AtomicBool::new(false),
+                flushed: Notify::new(),
+                synchronized: Notify::new(),
+                closed: Notify::new(),
+                response: Notify::new(),
+                statistics: Notify::new(),
+            }),
+            inner: Arc::new(ReceiverWrapper {
+                inner,
+                _m: Default::default(),
+            }),
+            waiters: Arc::new(sharded_slab::Slab::<oneshot::Sender<R>>::new_with_config::<
+                SlabCfg,
+            >()),
+        }
     }
 
     #[inline]
-    pub fn type_id(&self) -> TypeId {
-        self.inner.type_id()
+    pub fn resp_type_id(&self) -> TypeId {
+        self.context.resp_type_id
     }
 
     #[inline]
@@ -313,12 +340,16 @@ impl Receiver {
         self.context.need_flush.load(Ordering::SeqCst)
     }
 
-    #[inline]
     pub async fn reserve(&self) -> Permit {
         loop {
             let count = self.context.processing.load(Ordering::Relaxed);
             if count < self.context.limit {
-                let res = self.context.processing.compare_exchange(count, count + 1, Ordering::SeqCst, Ordering::SeqCst);
+                let res = self.context.processing.compare_exchange(
+                    count,
+                    count + 1,
+                    Ordering::SeqCst,
+                    Ordering::SeqCst,
+                );
                 if res.is_ok() {
                     break Permit {
                         fuse: false,
@@ -328,19 +359,22 @@ impl Receiver {
 
                 // continue
             } else {
-                self.context.response.notified()
-                    .await
+                self.context.response.notified().await
             }
         }
     }
 
-    #[inline]
     pub fn try_reserve(&self) -> Option<Permit> {
         loop {
             let count = self.context.processing.load(Ordering::Relaxed);
-            
+
             if count < self.context.limit {
-                let res = self.context.processing.compare_exchange(count, count + 1, Ordering::SeqCst, Ordering::SeqCst);
+                let res = self.context.processing.compare_exchange(
+                    count,
+                    count + 1,
+                    Ordering::SeqCst,
+                    Ordering::SeqCst,
+                );
                 if res.is_ok() {
                     break Some(Permit {
                         fuse: false,
@@ -356,7 +390,12 @@ impl Receiver {
     }
 
     #[inline]
-    pub fn send<M: Message>(&self, mid: u64, mut permit: Permit, msg: M) -> Result<(), SendError<M>> {
+    pub fn send<M: Message>(
+        &self,
+        mid: u64,
+        mut permit: Permit,
+        msg: M,
+    ) -> Result<(), SendError<M>> {
         let any_receiver = self.inner.typed();
         let receiver = any_receiver.dyn_typed_receiver::<M>();
         let res = receiver.send(mid, msg);
@@ -374,6 +413,7 @@ impl Receiver {
         let any_receiver = self.inner.typed();
         let receiver = any_receiver.dyn_typed_receiver::<M>();
         let res = receiver.send(mid, msg);
+        self.context.processing.fetch_add(1, Ordering::SeqCst);
 
         if !res.is_err() {
             self.context.need_flush.store(true, Ordering::SeqCst);
@@ -382,43 +422,75 @@ impl Receiver {
         res
     }
 
-    pub fn start_polling_events<M, E>(&self) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>> 
-        where 
-            M: Message,
-            E: crate::Error
+    pub fn start_polling_events<R, E>(
+        &self,
+    ) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>
+    where
+        R: Message,
+        E: crate::Error,
     {
         let ctx_clone = self.context.clone();
         let inner_clone = self.inner.clone();
+        let waiters = self
+            .waiters
+            .clone()
+            .downcast::<Slab<oneshot::Sender<R>>>()
+            .unwrap();
 
-        Box::new(move |bus| Box::pin(async move {
-            let any_receiver = inner_clone.poller();
-            let receiver = any_receiver.dyn_typed_receiver::<M, E>();
+        Box::new(move |bus| {
+            Box::pin(async move {
+                let any_receiver = inner_clone.poller();
+                let receiver = any_receiver.dyn_typed_receiver::<R, E>();
 
-            loop {
-                let event = poll_fn(move |ctx| receiver.poll_events(ctx))
-                    .await;
+                loop {
+                    let event = poll_fn(move |ctx| receiver.poll_events(ctx)).await;
 
-                match event {
-                    Event::Exited => {
-                        ctx_clone.closed.notify_waiters();
-                        break;
-                    },
-
-                    Event::Flushed => ctx_clone.flushed.notify_waiters(),
-                    Event::Synchronized(_res) => ctx_clone.synchronized.notify_waiters(),
-                    Event::Response(_mid, resp) => {
-                        ctx_clone.processing.fetch_sub(1, Ordering::SeqCst);
-                        ctx_clone.response.notify_one();
-
-                        match resp {
-                            Ok(_msg) => (),
-                            Err(err) => { bus.try_send(msgs::Error(Arc::new(err.into()))).ok(); }
+                    match event {
+                        Event::Exited => {
+                            ctx_clone.closed.notify_waiters();
+                            break;
                         }
-                    },
-                    _ => unimplemented!()
+
+                        Event::Flushed => ctx_clone.flushed.notify_waiters(),
+                        Event::Synchronized(_res) => ctx_clone.synchronized.notify_waiters(),
+                        Event::Response(mid, resp) => {
+                            ctx_clone.processing.fetch_sub(1, Ordering::SeqCst);
+                            ctx_clone.response.notify_one();
+
+                            match resp {
+                                Ok(msg) => {
+                                    if let Some(waiter) = waiters.take(mid as usize) {
+                                        if let Err(_msg) = waiter.send(msg) {
+                                            error!("Response cannot be processed!");
+                                        }
+                                    } else if TypeId::of::<R>() != TypeId::of::<()>() {
+                                        warn!("Non-void response has no listeners!");
+                                    }
+                                }
+                                Err(err) => {
+                                    bus.try_send(msgs::Error(Arc::new(err.into()))).ok();
+                                }
+                            }
+                        }
+                        _ => unimplemented!(),
+                    }
                 }
-            }
-        }))
+            })
+        })
+    }
+
+    #[inline]
+    pub(crate) fn add_response_waiter<R: Message>(
+        &self,
+        waiter: oneshot::Sender<R>,
+    ) -> Option<usize> {
+        let idx = self
+            .waiters
+            .downcast_ref::<Slab<oneshot::Sender<R>>>()
+            .unwrap()
+            .insert(waiter)?;
+
+        Some(idx)
     }
 
     // #[inline]
@@ -434,8 +506,7 @@ impl Receiver {
     #[inline]
     pub async fn close(&self) {
         if self.inner.close().is_ok() {
-            self.context.closed.notified()
-                .await
+            self.context.closed.notified().await
         } else {
             warn!("close failed!");
         }
@@ -444,8 +515,7 @@ impl Receiver {
     #[inline]
     pub async fn sync(&self) {
         if self.inner.sync().is_ok() {
-            self.context.synchronized.notified()
-                .await
+            self.context.synchronized.notified().await
         } else {
             warn!("sync failed!");
         }
@@ -454,9 +524,8 @@ impl Receiver {
     #[inline]
     pub async fn flush(&self) {
         if self.inner.flush().is_ok() {
-            self.context.flushed.notified()
-                .await;
-                
+            self.context.flushed.notified().await;
+
             self.context.need_flush.store(false, Ordering::SeqCst);
         } else {
             warn!("flush failed!");
diff --git a/src/receivers/buffer_unordered/async.rs b/src/receivers/buffer_unordered/async.rs
index e9571ed..018c498 100644
--- a/src/receivers/buffer_unordered/async.rs
+++ b/src/receivers/buffer_unordered/async.rs
@@ -7,9 +7,12 @@ use std::{
     task::{Context, Poll},
 };
 
-use crate::{receiver::{Action, Event, ReceiverStats, ReciveTypedReceiver, SendUntypedReceiver}, receivers::Request};
+use crate::{
+    receiver::{Action, Event, ReceiverStats, ReciveTypedReceiver, SendUntypedReceiver},
+    receivers::Request,
+};
 use anyhow::Result;
-use futures::{Future, StreamExt, stream::FuturesUnordered};
+use futures::{stream::FuturesUnordered, Future, StreamExt};
 
 use super::{BufferUnorderedConfig, BufferUnorderedStats};
 use crate::{
@@ -20,7 +23,6 @@ use crate::{
 use parking_lot::Mutex;
 use tokio::sync::mpsc;
 
-
 fn buffer_unordered_poller<T, M, R, E>(
     mut rx: mpsc::UnboundedReceiver<Request<M>>,
     bus: Bus,
@@ -33,7 +35,7 @@ where
     T: AsyncHandler<M, Response = R, Error = E> + 'static,
     M: Message,
     R: Message,
-    E: crate::Error
+    E: crate::Error,
 {
     let ut = ut.downcast::<T>().unwrap();
     let mut queue = FuturesUnordered::new();
@@ -46,33 +48,33 @@ where
         if !rx_closed && !need_flush && !need_sync {
             while queue.len() < cfg.max_parallel {
                 match rx.poll_recv(cx) {
-                    Poll::Ready(Some(a)) => {
-                        match a {
-                            Request::Request(mid, msg) => {
-                                stats.buffer.fetch_sub(1, Ordering::Relaxed);
-                                stats.parallel.fetch_add(1, Ordering::Relaxed);
+                    Poll::Ready(Some(a)) => match a {
+                        Request::Request(mid, msg) => {
+                            stats.buffer.fetch_sub(1, Ordering::Relaxed);
+                            stats.parallel.fetch_add(1, Ordering::Relaxed);
 
-                                let bus = bus.clone();
-                                let ut = ut.clone();
-                                queue.push(tokio::task::spawn(async move { (mid, ut.handle(msg, &bus).await) }));
-                            },
-                            Request::Action(Action::Flush) => need_flush = true,
-                            Request::Action(Action::Sync) => need_sync = true,
-                            Request::Action(Action::Close) => rx.close(),
-                            _ => unimplemented!()
+                            let bus = bus.clone();
+                            let ut = ut.clone();
+                            queue.push(tokio::task::spawn(async move {
+                                (mid, ut.handle(msg, &bus).await)
+                            }));
                         }
+                        Request::Action(Action::Flush) => need_flush = true,
+                        Request::Action(Action::Sync) => need_sync = true,
+                        Request::Action(Action::Close) => rx.close(),
+                        _ => unimplemented!(),
                     },
                     Poll::Ready(None) => {
                         need_sync = true;
                         rx_closed = true;
-                    },
+                    }
                     Poll::Pending => break,
                 }
             }
         }
 
         let queue_len = queue.len();
-        
+
         loop {
             if queue_len != 0 {
                 loop {
@@ -80,7 +82,7 @@ where
                         Poll::Pending => return Poll::Pending,
                         Poll::Ready(Some(Ok((mid, res)))) => {
                             stx.send(Event::Response(mid, res)).ok();
-                        },
+                        }
                         Poll::Ready(None) => break,
                         _ => {}
                     }
@@ -98,7 +100,7 @@ where
                         Poll::Pending => {
                             sync_future = Some(fut);
                             return Poll::Pending;
-                        },
+                        }
                         Poll::Ready(res) => {
                             need_sync = false;
                             stx.send(Event::Synchronized(res)).ok();
@@ -107,9 +109,7 @@ where
                 } else {
                     let ut = ut.clone();
                     let bus_clone = bus.clone();
-                    sync_future.replace(Box::pin(async move { 
-                        ut.sync(&bus_clone).await 
-                    }));
+                    sync_future.replace(Box::pin(async move { ut.sync(&bus_clone).await }));
                 }
             } else {
                 break;
@@ -117,16 +117,20 @@ where
         }
 
         if queue_len == queue.len() {
-            return if rx_closed { Poll::Ready(()) } else { Poll::Pending };
+            return if rx_closed {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            };
         }
     })
 }
 
-pub struct BufferUnorderedAsync<M, R = (), E = anyhow::Error> 
-    where 
-        M: Message,
-        R: Message,
-        E: crate::Error
+pub struct BufferUnorderedAsync<M, R = (), E = anyhow::Error>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     tx: mpsc::UnboundedSender<Request<M>>,
     stats: Arc<BufferUnorderedStats>,
@@ -134,16 +138,22 @@ pub struct BufferUnorderedAsync<M, R = (), E = anyhow::Error>
 }
 
 impl<T, M, R, E> ReceiverSubscriberBuilder<T, M, R, E> for BufferUnorderedAsync<M, R, E>
-    where
-        T: AsyncHandler<M, Response = R, Error = E> + 'static,
-        R: Message,
-        M: Message,
-        E: crate::Error
+where
+    T: AsyncHandler<M, Response = R, Error = E> + 'static,
+    R: Message,
+    M: Message,
+    E: crate::Error,
 {
     type Config = BufferUnorderedConfig;
 
-    fn build(cfg: Self::Config) -> (Self, Box<dyn FnOnce(Untyped) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>>)
-    {
+    fn build(
+        cfg: Self::Config,
+    ) -> (
+        Self,
+        Box<
+            dyn FnOnce(Untyped) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>,
+        >,
+    ) {
         let stats = Arc::new(BufferUnorderedStats {
             buffer: AtomicU64::new(0),
             buffer_total: AtomicU64::new(cfg.buffer_size as _),
@@ -157,39 +167,48 @@ impl<T, M, R, E> ReceiverSubscriberBuilder<T, M, R, E> for BufferUnorderedAsync<
 
         let poller = Box::new(move |ut| {
             Box::new(move |bus| {
-                Box::pin(buffer_unordered_poller::<T, M, R, E>(rx, bus, ut, stats_clone, cfg, stx))
-                    as Pin<Box<dyn Future<Output = ()> + Send>>
+                Box::pin(buffer_unordered_poller::<T, M, R, E>(
+                    rx,
+                    bus,
+                    ut,
+                    stats_clone,
+                    cfg,
+                    stx,
+                )) as Pin<Box<dyn Future<Output = ()> + Send>>
             }) as Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>
         });
 
-        (BufferUnorderedAsync::<M, R, E> {
-            tx,
-            stats,
-            srx: Mutex::new(srx),
-        }, poller)
+        (
+            BufferUnorderedAsync::<M, R, E> {
+                tx,
+                stats,
+                srx: Mutex::new(srx),
+            },
+            poller,
+        )
     }
 }
 
-impl<M, R, E> SendUntypedReceiver for BufferUnorderedAsync<M, R, E> 
-    where
-        M: Message,
-        R: Message,
-        E: crate::Error
+impl<M, R, E> SendUntypedReceiver for BufferUnorderedAsync<M, R, E>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     fn send(&self, m: Action) -> Result<(), SendError<Action>> {
         match self.tx.send(Request::Action(m)) {
             Ok(_) => Ok(()),
             Err(mpsc::error::SendError(Request::Action(msg))) => Err(SendError::Closed(msg)),
-            _ => unimplemented!()
+            _ => unimplemented!(),
         }
     }
 }
 
-impl<M, R, E> SendTypedReceiver<M> for BufferUnorderedAsync<M, R, E> 
-    where
-        M: Message,
-        R: Message,
-        E: crate::Error
+impl<M, R, E> SendTypedReceiver<M> for BufferUnorderedAsync<M, R, E>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     fn send(&self, mid: u64, m: M) -> Result<(), SendError<M>> {
         match self.tx.send(Request::Request(mid, m)) {
@@ -199,16 +218,16 @@ impl<M, R, E> SendTypedReceiver<M> for BufferUnorderedAsync<M, R, E>
                 Ok(())
             }
             Err(mpsc::error::SendError(Request::Request(_, msg))) => Err(SendError::Closed(msg)),
-            _ => unimplemented!()
+            _ => unimplemented!(),
         }
     }
 }
 
-impl<M, R, E> ReciveTypedReceiver<R, E> for BufferUnorderedAsync<M, R, E> 
-    where
-        M: Message,
-        R: Message,
-        E: crate::Error
+impl<M, R, E> ReciveTypedReceiver<R, E> for BufferUnorderedAsync<M, R, E>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     fn poll_events(&self, ctx: &mut Context<'_>) -> Poll<Event<R, E>> {
         let poll = self.srx.lock().poll_recv(ctx);
@@ -218,4 +237,4 @@ impl<M, R, E> ReciveTypedReceiver<R, E> for BufferUnorderedAsync<M, R, E>
             Poll::Ready(None) => Poll::Ready(Event::Exited),
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/receivers/buffer_unordered/sync.rs b/src/receivers/buffer_unordered/sync.rs
index 92756a3..fd55f22 100644
--- a/src/receivers/buffer_unordered/sync.rs
+++ b/src/receivers/buffer_unordered/sync.rs
@@ -7,20 +7,22 @@ use std::{
     task::{Context, Poll},
 };
 
-use crate::{receiver::{Action, Event, ReceiverStats, ReciveTypedReceiver, SendUntypedReceiver}, receivers::Request};
+use crate::{
+    receiver::{Action, Event, ReceiverStats, ReciveTypedReceiver, SendUntypedReceiver},
+    receivers::Request,
+};
 use anyhow::Result;
-use futures::{Future, StreamExt, stream::FuturesUnordered};
+use futures::{stream::FuturesUnordered, Future, StreamExt};
 
 use super::{BufferUnorderedConfig, BufferUnorderedStats};
 use crate::{
     builder::ReceiverSubscriberBuilder,
     receiver::{SendError, SendTypedReceiver},
-    Handler, Bus, Message, Untyped,
+    Bus, Handler, Message, Untyped,
 };
 use parking_lot::Mutex;
 use tokio::sync::mpsc;
 
-
 fn buffer_unordered_poller<T, M, R, E>(
     mut rx: mpsc::UnboundedReceiver<Request<M>>,
     bus: Bus,
@@ -33,7 +35,7 @@ where
     T: Handler<M, Response = R, Error = E> + 'static,
     M: Message,
     R: Message,
-    E: crate::Error
+    E: crate::Error,
 {
     let ut = ut.downcast::<T>().unwrap();
     let mut queue = FuturesUnordered::new();
@@ -46,33 +48,33 @@ where
         if !rx_closed && !need_flush && !need_sync {
             while queue.len() < cfg.max_parallel {
                 match rx.poll_recv(cx) {
-                    Poll::Ready(Some(a)) => {
-                        match a {
-                            Request::Request(mid, msg) => {
-                                stats.buffer.fetch_sub(1, Ordering::Relaxed);
-                                stats.parallel.fetch_add(1, Ordering::Relaxed);
+                    Poll::Ready(Some(a)) => match a {
+                        Request::Request(mid, msg) => {
+                            stats.buffer.fetch_sub(1, Ordering::Relaxed);
+                            stats.parallel.fetch_add(1, Ordering::Relaxed);
 
-                                let bus = bus.clone();
-                                let ut = ut.clone();
-                                queue.push( tokio::task::spawn_blocking(move || (mid, ut.handle(msg, &bus))));
-                            },
-                            Request::Action(Action::Flush) => need_flush = true,
-                            Request::Action(Action::Sync) => need_sync = true,
-                            Request::Action(Action::Close) => rx.close(),
-                            _ => unimplemented!()
+                            let bus = bus.clone();
+                            let ut = ut.clone();
+                            queue.push(tokio::task::spawn_blocking(move || {
+                                (mid, ut.handle(msg, &bus))
+                            }));
                         }
+                        Request::Action(Action::Flush) => need_flush = true,
+                        Request::Action(Action::Sync) => need_sync = true,
+                        Request::Action(Action::Close) => rx.close(),
+                        _ => unimplemented!(),
                     },
                     Poll::Ready(None) => {
                         need_sync = true;
                         rx_closed = true;
-                    },
+                    }
                     Poll::Pending => break,
                 }
             }
         }
 
         let queue_len = queue.len();
-        
+
         loop {
             if queue_len != 0 {
                 loop {
@@ -80,7 +82,7 @@ where
                         Poll::Pending => return Poll::Pending,
                         Poll::Ready(Some(Ok((mid, res)))) => {
                             stx.send(Event::Response(mid, res)).ok();
-                        },
+                        }
                         Poll::Ready(None) => break,
                         _ => {}
                     }
@@ -98,7 +100,7 @@ where
                         Poll::Pending => {
                             sync_future = Some(fut);
                             return Poll::Pending;
-                        },
+                        }
                         Poll::Ready(res) => {
                             need_sync = false;
                             stx.send(Event::Synchronized(res)).ok();
@@ -108,7 +110,9 @@ where
                     let ut = ut.clone();
                     let bus_clone = bus.clone();
                     sync_future.replace(Box::pin(async move {
-                        tokio::task::spawn_blocking(move || ut.sync(&bus_clone)).await.unwrap()
+                        tokio::task::spawn_blocking(move || ut.sync(&bus_clone))
+                            .await
+                            .unwrap()
                     }));
                 }
             } else {
@@ -117,16 +121,20 @@ where
         }
 
         if queue_len == queue.len() {
-            return if rx_closed { Poll::Ready(()) } else { Poll::Pending };
+            return if rx_closed {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            };
         }
     })
 }
 
-pub struct BufferUnorderedSync<M, R = (), E = anyhow::Error> 
-    where 
-        M: Message,
-        R: Message,
-        E: crate::Error
+pub struct BufferUnorderedSync<M, R = (), E = anyhow::Error>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     tx: mpsc::UnboundedSender<Request<M>>,
     stats: Arc<BufferUnorderedStats>,
@@ -134,15 +142,22 @@ pub struct BufferUnorderedSync<M, R = (), E = anyhow::Error>
 }
 
 impl<T, M, R, E> ReceiverSubscriberBuilder<T, M, R, E> for BufferUnorderedSync<M, R, E>
-    where
-        T: Handler<M, Response = R, Error = E> + 'static,
-        R: Message,
-        M: Message,
-        E: crate::Error
+where
+    T: Handler<M, Response = R, Error = E> + 'static,
+    R: Message,
+    M: Message,
+    E: crate::Error,
 {
     type Config = BufferUnorderedConfig;
 
-    fn build(cfg: Self::Config) -> (Self, Box<dyn FnOnce(Untyped) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>>) {
+    fn build(
+        cfg: Self::Config,
+    ) -> (
+        Self,
+        Box<
+            dyn FnOnce(Untyped) -> Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>,
+        >,
+    ) {
         let stats = Arc::new(BufferUnorderedStats {
             buffer: AtomicU64::new(0),
             buffer_total: AtomicU64::new(cfg.buffer_size as _),
@@ -156,40 +171,48 @@ impl<T, M, R, E> ReceiverSubscriberBuilder<T, M, R, E> for BufferUnorderedSync<M
 
         let poller = Box::new(move |ut| {
             Box::new(move |bus| {
-                Box::pin(buffer_unordered_poller::<T, M, R, E>(rx, bus, ut, stats_clone, cfg, stx))
-                    as Pin<Box<dyn Future<Output = ()> + Send>>
+                Box::pin(buffer_unordered_poller::<T, M, R, E>(
+                    rx,
+                    bus,
+                    ut,
+                    stats_clone,
+                    cfg,
+                    stx,
+                )) as Pin<Box<dyn Future<Output = ()> + Send>>
             }) as Box<dyn FnOnce(Bus) -> Pin<Box<dyn Future<Output = ()> + Send>>>
         });
 
-        (BufferUnorderedSync::<M, R, E> {
-            tx,
-            stats,
-            srx: Mutex::new(srx),
-        }, poller)
+        (
+            BufferUnorderedSync::<M, R, E> {
+                tx,
+                stats,
+                srx: Mutex::new(srx),
+            },
+            poller,
+        )
     }
 }
 
-impl<M, R, E> SendUntypedReceiver for BufferUnorderedSync<M, R, E> 
-    where
-        M: Message,
-        R: Message,
-        E: crate::Error
+impl<M, R, E> SendUntypedReceiver for BufferUnorderedSync<M, R, E>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     fn send(&self, msg: Action) -> Result<(), SendError<Action>> {
         match self.tx.send(Request::Action(msg)) {
             Ok(_) => Ok(()),
             Err(mpsc::error::SendError(Request::Action(msg))) => Err(SendError::Closed(msg)),
-            _ => unimplemented!()
+            _ => unimplemented!(),
         }
     }
 }
 
-
-impl<M, R, E> SendTypedReceiver<M> for BufferUnorderedSync<M, R, E> 
-    where
-        M: Message,
-        R: Message,
-        E: crate::Error
+impl<M, R, E> SendTypedReceiver<M> for BufferUnorderedSync<M, R, E>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     fn send(&self, mid: u64, m: M) -> Result<(), SendError<M>> {
         match self.tx.send(Request::Request(mid, m)) {
@@ -199,16 +222,16 @@ impl<M, R, E> SendTypedReceiver<M> for BufferUnorderedSync<M, R, E>
                 Ok(())
             }
             Err(mpsc::error::SendError(Request::Request(_, msg))) => Err(SendError::Closed(msg)),
-            _ => unimplemented!()
+            _ => unimplemented!(),
         }
     }
 }
 
-impl<M, R, E> ReciveTypedReceiver<R, E> for BufferUnorderedSync<M, R, E> 
-    where
-        M: Message,
-        R: Message,
-        E: crate::Error
+impl<M, R, E> ReciveTypedReceiver<R, E> for BufferUnorderedSync<M, R, E>
+where
+    M: Message,
+    R: Message,
+    E: crate::Error,
 {
     fn poll_events(&self, ctx: &mut Context<'_>) -> Poll<Event<R, E>> {
         let poll = self.srx.lock().poll_recv(ctx);
@@ -218,4 +241,4 @@ impl<M, R, E> ReciveTypedReceiver<R, E> for BufferUnorderedSync<M, R, E>
             Poll::Ready(None) => Poll::Ready(Event::Exited),
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/receivers/mod.rs b/src/receivers/mod.rs
index dcf850b..3daa2cb 100644
--- a/src/receivers/mod.rs
+++ b/src/receivers/mod.rs
@@ -4,25 +4,20 @@ mod buffer_unordered;
 // mod synchronize_batched;
 // mod synchronized;
 
-
 // mod mpsc;
 // mod mpsc {
 //     pub use super::mpsc_futures::*;
 // }
 
-pub use buffer_unordered::{
-    BufferUnorderedAsync, BufferUnorderedConfig,
-    BufferUnorderedSync,
-};
+pub use buffer_unordered::{BufferUnorderedAsync, BufferUnorderedConfig, BufferUnorderedSync};
 
 use crate::receiver::Action;
 
 pub(crate) enum Request<M> {
     Action(Action),
-    Request(u64, M)
+    Request(u64, M),
 }
 
-
 // pub use buffer_unordered_batched::{
 //     BufferUnorderedBatchedAsync, BufferUnorderedBatchedAsyncSubscriber, BufferUnorderedBatchedConfig,
 //     BufferUnorderedBatchedSync, BufferUnorderedBatchedSyncSubscriber,