Function gio_sys::g_file_unmount_mountable_with_operation

pub unsafe extern fn g_file_unmount_mountable_with_operation(file: *mut GFile,
                                                             flags: GMountUnmountFlags,
                                                             mount_operation: *mut GMountOperation,
                                                             cancellable: *mut GCancellable,
                                                             callback: GAsyncReadyCallback,
                                                             user_data: gpointer)