Function gio_sys::g_mount_unmount_with_operation

pub unsafe extern fn g_mount_unmount_with_operation(mount: *mut GMount,
                                                    flags: GMountUnmountFlags,
                                                    mount_operation: *mut GMountOperation,
                                                    cancellable: *mut GCancellable,
                                                    callback: GAsyncReadyCallback,
                                                    user_data: gpointer)