stream_muxer(yamux): add ReadWriteLock to YamuxStream to prevent concurrent read/write corruption

Introduce a read/write lock abstraction and integrate it into `YamuxStream` so that simultaneous
reads and writes do not interleave, eliminating potential data corruption and race conditions.

Major changes:
- Abstract `ReadWriteLock` into its own util module
- Integrate locking into YamuxStream for `write` operations
- Ensure tests pass for lock correctness
- Fix lint & type issues discovered during review

Closes #793

libp2p/stream_muxer/mplex/mplex_stream.py

@@ -1,5 +1,3 @@
-from collections.abc import AsyncGenerator
-from contextlib import asynccontextmanager
 from types import (
     TracebackType,
 )
@@ -15,6 +13,7 @@ from libp2p.abc import (
 from libp2p.stream_muxer.exceptions import (
     MuxedConnUnavailable,
 )
+from libp2p.stream_muxer.rw_lock import ReadWriteLock
 
 from .constants import (
     HeaderTags,
@@ -34,72 +33,6 @@ if TYPE_CHECKING:
     )
 
 
-class ReadWriteLock:
-    """
-    A read-write lock that allows multiple concurrent readers
-    or one exclusive writer, implemented using Trio primitives.
-    """
-
-    def __init__(self) -> None:
-        self._readers = 0
-        self._readers_lock = trio.Lock()  # Protects access to _readers count
-        self._writer_lock = trio.Semaphore(1)  # Allows only one writer at a time
-
-    async def acquire_read(self) -> None:
-        """Acquire a read lock. Multiple readers can hold it simultaneously."""
-        try:
-            async with self._readers_lock:
-                if self._readers == 0:
-                    await self._writer_lock.acquire()
-                self._readers += 1
-        except trio.Cancelled:
-            raise
-
-    async def release_read(self) -> None:
-        """Release a read lock."""
-        async with self._readers_lock:
-            if self._readers == 1:
-                self._writer_lock.release()
-            self._readers -= 1
-
-    async def acquire_write(self) -> None:
-        """Acquire an exclusive write lock."""
-        try:
-            await self._writer_lock.acquire()
-        except trio.Cancelled:
-            raise
-
-    def release_write(self) -> None:
-        """Release the exclusive write lock."""
-        self._writer_lock.release()
-
-    @asynccontextmanager
-    async def read_lock(self) -> AsyncGenerator[None, None]:
-        """Context manager for acquiring and releasing a read lock safely."""
-        acquire = False
-        try:
-            await self.acquire_read()
-            acquire = True
-            yield
-        finally:
-            if acquire:
-                with trio.CancelScope() as scope:
-                    scope.shield = True
-                    await self.release_read()
-
-    @asynccontextmanager
-    async def write_lock(self) -> AsyncGenerator[None, None]:
-        """Context manager for acquiring and releasing a write lock safely."""
-        acquire = False
-        try:
-            await self.acquire_write()
-            acquire = True
-            yield
-        finally:
-            if acquire:
-                self.release_write()
-
-
 class MplexStream(IMuxedStream):
     """
     reference: https://github.com/libp2p/go-mplex/blob/master/stream.go