Mix: temporal as stream extension (#861)

* forward msgs immediately without any processing

* Mix: Offload transmission rate and message processing from libp2p behaviour/handler

* Mix: Core skeleton used in `MixService`

* rename Processor to MessageBlend

* Mix: Implement Persistent Transmission (Tier 1) (#845)

* Mix: Add Persistent Transmission (Tier 1)

* add test

* define Coin struct with Uniform distribution for fast repeated sampling

* use ChaCha12Rng for Coin

* improve comment

* Mix: Implement Temporal Processor (Tier 2) (#846)

* Mix: Add Persistent Transmission (Tier 1)

* Mix: Implement TemporalProcessor

* use pub(crate)

* Mix: Use TemporalProcessor in MessageBlend (#847)

* Mix: Add Persistent Transmission (Tier 1)

* Mix: Implement TemporalProcessor

* Mix: Use TemporalProcessor in MessageBlend

* remove duplicate members in Cargo.toml

* Implement persistent transmission as stream trait extension

* Replicate test for stream version

* Temporal processor as stream extension

---------

Co-authored-by: Youngjoon Lee <5462944+youngjoon-lee@users.noreply.github.com>

nomos-mix/core/src/message_blend/temporal.rs

@@ -5,7 +5,7 @@ use std::{
     time::Duration,
 };
 
-use futures::{Future, Stream};
+use futures::{Future, Stream, StreamExt};
 use rand::Rng;
 use serde::{Deserialize, Serialize};
 use tokio::time;
@@ -71,7 +71,7 @@ impl<M> TemporalProcessor<M> {
 
 impl<M> Stream for TemporalProcessor<M>
 where
-    M: Unpin + Clone + 'static,
+    M: Unpin,
 {
     type Item = M;
 
@@ -97,3 +97,40 @@ where
         Poll::Pending
     }
 }
+
+pub struct TemporalStream<S>
+where
+    S: Stream,
+{
+    processor: TemporalProcessor<S::Item>,
+    wrapped_stream: S,
+}
+
+impl<S> Stream for TemporalStream<S>
+where
+    S: Stream + Unpin,
+    S::Item: Unpin,
+{
+    type Item = S::Item;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        if let Poll::Ready(Some(item)) = self.wrapped_stream.poll_next_unpin(cx) {
+            self.processor.push_message(item);
+        }
+        self.processor.poll_next_unpin(cx)
+    }
+}
+#[allow(dead_code)] // TODO: Remove when integrating into blend
+pub trait TemporalProcessorExt: Stream {
+    fn to_temporal_stream(self, settings: TemporalProcessorSettings) -> TemporalStream<Self>
+    where
+        Self: Sized,
+    {
+        TemporalStream {
+            processor: TemporalProcessor::new(settings),
+            wrapped_stream: self,
+        }
+    }
+}
+
+impl<T> TemporalProcessorExt for T where T: Stream {}