asyncore.file_wrapper duplicates file descriptor of given file and closes it in it's close method.

But unlike socket.socket class it does not automatically call close when object is garbage collected.

Users of regular sockets and asyncore.dispatcher do not experience resource leaks when they forget to call self.close() in handle_close().

But people using file_dispatcher do loose file descriptor every time file_wrapper object is garbage collected without calling self.close() first.