feat: small speed up to the aio message reader (#273)

src/dbus_fast/aio/message_reader.pxd

@@ -3,3 +3,11 @@
 import cython
 
 from .._private.unmarshaller cimport Unmarshaller
+
+
+cpdef _message_reader(
+    Unmarshaller unmarshaller,
+    object process,
+    object finalize,
+    bint negotiate_unix_fd
+)

src/dbus_fast/aio/message_reader.py

@@ -1,21 +1,18 @@
 import logging
 import socket
+from functools import partial
 from typing import Callable, Optional
 
 from .._private.unmarshaller import Unmarshaller
 from ..message import Message
 
 
-def build_message_reader(
-    sock: Optional[socket.socket],
+def _message_reader(
+    unmarshaller: Unmarshaller,
     process: Callable[[Message], None],
     finalize: Callable[[Optional[Exception]], None],
     negotiate_unix_fd: bool,
-) -> Callable[[], None]:
-    """Build a callable that reads messages from the unmarshaller and passes them to the process function."""
-    unmarshaller = Unmarshaller(None, sock, negotiate_unix_fd)
-
-    def _message_reader() -> None:
+) -> None:
     """Reads messages from the unmarshaller and passes them to the process function."""
     try:
         while True:
@@ -25,9 +22,7 @@ def build_message_reader(
             try:
                 process(message)
             except Exception as e:
-                    logging.error(
-                        "Unexpected error processing message: %s", exc_info=True
-                    )
+                logging.error("Unexpected error processing message: %s", exc_info=True)
             # If we are not negotiating unix fds, we can stop reading as soon as we have
             # the buffer is empty as asyncio will call us again when there is more data.
             if (
@@ -38,4 +33,13 @@ def build_message_reader(
     except Exception as e:
         finalize(e)
 
-    return _message_reader
+
+def build_message_reader(
+    sock: Optional[socket.socket],
+    process: Callable[[Message], None],
+    finalize: Callable[[Optional[Exception]], None],
+    negotiate_unix_fd: bool,
+) -> Callable[[], None]:
+    """Build a callable that reads messages from the unmarshaller and passes them to the process function."""
+    unmarshaller = Unmarshaller(None, sock, negotiate_unix_fd)
+    return partial(_message_reader, unmarshaller, process, finalize, negotiate_unix_fd)