Starts an asynchronous eject on a mountable.
When this operation has completed, @callback will be called with
@user_user data, and the operation can be finalized with
g_file_eject_mountable_with_operation_finish().
If @cancellable 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.
Starts an asynchronous eject on a mountable. When this operation has completed, @callback will be called with @user_user data, and the operation can be finalized with g_file_eject_mountable_with_operation_finish().
If @cancellable 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.