add: g_io_add_watch (conn->chan, G_IO_IN, server_cb, conn);
context: bacon_message_connection_set_callback (BaconMessageConnection *conn,				       BaconMessageReceivedFunc func,				       gpointer user_data){	g_return_if_fail (conn != NULL);	g_assert (conn->is_server == TRUE);	conn->func = func;	conn->data = user_data;}