If an asynchronous operation is started successfully, the caller is given back a GnomeVFSAsyncHandle object that can be used to stop the operation after it has been started, by using the following call:
GnomeVFSResult gnome_vfs_async_cancel (GnomeVFSAsyncHandle *handle)
In the case of file ``open'' and ``create'' operations, the GnomeVFSAsyncHandle object can also be used to request read/write operations on the file after it has been opened or created.