feat: implement get_remote_address via delegation pattern

libp2p/stream_muxer/mplex/mplex.py

@@ -365,3 +365,7 @@ class Mplex(IMuxedConn):
                 await send_channel.aclose()
         self.event_closed.set()
         await self.new_stream_send_channel.aclose()
+
+    def get_remote_address(self) -> Optional[tuple[str, int]]:
+        """Delegate to the underlying Mplex connection's secured_conn."""
+        return self.secured_conn.get_remote_address()

libp2p/stream_muxer/mplex/mplex_stream.py

@@ -1,5 +1,6 @@
 from typing import (
     TYPE_CHECKING,
+    Optional,
 )
 
 import trio
@@ -252,3 +253,7 @@ class MplexStream(IMuxedStream):
         """
         self.write_deadline = ttl
         return True
+
+    def get_remote_address(self) -> Optional[tuple[str, int]]:
+        """Delegate to the parent Mplex connection."""
+        return self.muxed_conn.get_remote_address()