gFilePollMountable(object, cancellable = NULL, callback, user.data = NULL)objectGFile.cancellableGCancellable object, NULL to ignore.callbackGAsyncReadyCallback to call when the request is satisfied, or NULL.user.datacancellable is not NULL, then the operation can be cancelled by
triggering the cancellable object from another thread. If the operation
was cancelled, the error G_IO_ERROR_CANCELLED will be returned.
When the operation is finished, callback will be called. You can then call
gFileMountMountableFinish to get the result of the operation.
Since 2.22