Cosmetic changes

src/python/grpcio/grpc/_cython/_cygrpc/aio/iomgr/iomgr.pyx.pxi

@@ -123,6 +123,8 @@ cdef grpc_error* asyncio_socket_listen(grpc_custom_socket* grpc_socket) with gil
 
 
 def _asyncio_apply_socket_options(object s):
+    # TODO(https://github.com/grpc/grpc/issues/20667)	
+    # Connects the so_reuse_port option to channel arguments
     s.setsockopt(native_socket.SOL_SOCKET, native_socket.SO_REUSEADDR, 1)
     s.setsockopt(native_socket.IPPROTO_TCP, native_socket.TCP_NODELAY, True)
 

src/python/grpcio/grpc/_cython/_cygrpc/aio/server.pyx.pxi

@@ -227,7 +227,6 @@ async def _handle_rpc(list generic_handlers, RPCState rpc_state, object loop):
         # TODO(lidiz) return unimplemented error to client side
         raise NotImplementedError()
 
-    try:
     # TODO(lidiz) extend to all 4 types of RPC
     if not method_handler.request_streaming and method_handler.response_streaming:
         await _handle_unary_stream_rpc(method_handler,
@@ -239,9 +238,6 @@ async def _handle_rpc(list generic_handlers, RPCState rpc_state, object loop):
                                     loop)
     else:
         raise NotImplementedError()
-    except Exception as e:
-        _LOGGER.exception(e)
-        raise
 
 
 class _RequestCallError(Exception): pass
@@ -473,7 +469,7 @@ cdef class AioServer:
         If the Cython representation is deallocated without underlying objects
         freed, raise an RuntimeError.
         """
-        # NOTE(lidiz) if users create server, and then dealloc it immediately.
+        # TODO(lidiz) if users create server, and then dealloc it immediately.
         # There is a potential memory leak of created Core server.
         if self._status != AIO_SERVER_STATUS_STOPPED:
             _LOGGER.warn(