Feat: Adding Yamux as default multiplexer, keeping Mplex as fallback (#538)

* feat: Replace mplex with yamux as default multiplexer in py-libp2p

* Retain Mplex alongside Yamux in new_swarm with messaging that Yamux is preferred

* moved !BBHII to a constant YAMUX_HEADER_FORMAT at the top of yamux.py with a comment explaining its structure

* renamed the news fragment to 534.feature.rst and updated the description

* renamed the news fragment to 534.feature.rst and updated the description

* added a docstring to clarify that Yamux does not support deadlines natively

* Remove the __main__ block entirely from test_yamux.py

* Replaced the print statements in test_yamux.py with logging.debug

* Added a comment linking to the spec for clarity

* Raise NotImplementedError in YamuxStream.set_deadline per review

* Add muxed_conn to YamuxStream and test deadline NotImplementedError

* Fix Yamux implementation to meet libp2p spec

* Fix None handling in YamuxStream.read and Yamux.read_stream

* Fix test_connected_peers.py to correctly handle peer connections

* fix: Ensure StreamReset is raised on read after local reset in yamux

* fix: Map MuxedStreamError to StreamClosed in NetStream.write for Yamux

* fix: Raise MuxedStreamReset in Yamux.read_stream for closed streams

* fix: Correct Yamux stream read behavior for NetStream tests

Fixed 	est_net_stream_read_after_remote_closed by updating NetStream.read to raise StreamEOF when the stream is remotely closed and no data is available, aligning with test expectations and Fixed 	est_net_stream_read_until_eof by modifying YamuxStream.read to block until the stream is closed (
ecv_closed=True) for
=-1 reads, ensuring data is only returned after remote closure.

* fix: Correct Yamux stream read behavior for NetStream tests

Fixed 	est_net_stream_read_after_remote_closed by updating NetStream.read to raise StreamEOF when the stream is remotely closed and no data is available, aligning with test expectations and Fixed 	est_net_stream_read_until_eof by modifying YamuxStream.read to block until the stream is closed (
ecv_closed=True) for
=-1 reads, ensuring data is only returned after remote closure.

* fix: raise StreamEOF when reading from closed stream with empty buffer

* fix: prioritize returning buffered data even after stream reset

* fix: prioritize returning buffered data even after stream reset

* fix: Ensure test_net_stream_read_after_remote_closed_and_reset passes in full suite

* fix: Add __init__.py to yamux module to fix documentation build

* fix: Add __init__.py to yamux module to fix documentation build

* fix: Add libp2p.stream_muxer.yamux to libp2p.stream_muxer.rst toctree

* fix: Correct title underline length in libp2p.stream_muxer.yamux.rst

* fix: Add a = so that is matches the libp2p.stream\_muxer.yamux length

* fix(tests): Resolve race condition in network notification test

* fix: fixing failing tests and examples with yamux and noise

* refactor: remove debug logging and improve x25519 tests

* fix: Add functionality for users to choose between Yamux and Mplex

* fix: increased trio sleep to 0.1 sec for slow environment

* feat: Add test for switching between Yamux and mplex

* refactor: move host fixtures to interop tests

* chore: Update __init__.py removing unused import

removed unused
```python
import os
import logging
```

* lint: fix import order

* fix: Resolve conftest.py conflict by removing trio test support

* fix: Resolve test skipping by keeping trio test support

* Fix: add a newline at end of the file

---------

Co-authored-by: acul71 <luca.pisani@birdo.net>
Co-authored-by: acul71 <34693171+acul71@users.noreply.github.com>

libp2p/stream_muxer/muxer_multistream.py

@@ -2,6 +2,8 @@ from collections import (
     OrderedDict,
 )
 
+import trio
+
 from libp2p.abc import (
     IMuxedConn,
     IRawConnection,
@@ -24,6 +26,10 @@ from libp2p.protocol_muxer.multiselect_client import (
 from libp2p.protocol_muxer.multiselect_communicator import (
     MultiselectCommunicator,
 )
+from libp2p.stream_muxer.yamux.yamux import (
+    PROTOCOL_ID,
+    Yamux,
+)
 
 # FIXME: add negotiate timeout to `MuxerMultistream`
 DEFAULT_NEGOTIATE_TIMEOUT = 60
@@ -44,7 +50,7 @@ class MuxerMultistream:
     def __init__(self, muxer_transports_by_protocol: TMuxerOptions) -> None:
         self.transports = OrderedDict()
         self.multiselect = Multiselect()
-        self.multiselect_client = MultiselectClient()
+        self.multistream_client = MultiselectClient()
         for protocol, transport in muxer_transports_by_protocol.items():
             self.add_transport(protocol, transport)
 
@@ -81,5 +87,18 @@ class MuxerMultistream:
         return self.transports[protocol]
 
     async def new_conn(self, conn: ISecureConn, peer_id: ID) -> IMuxedConn:
-        transport_class = await self.select_transport(conn)
+        communicator = MultiselectCommunicator(conn)
+        protocol = await self.multistream_client.select_one_of(
+            tuple(self.transports.keys()), communicator
+        )
+        transport_class = self.transports[protocol]
+        if protocol == PROTOCOL_ID:
+            async with trio.open_nursery():
+
+                def on_close() -> None:
+                    pass
+
+                return Yamux(
+                    conn, peer_id, is_initiator=conn.is_initiator, on_close=on_close
+                )
         return transport_class(conn, peer_id)