pub unsafe extern "C" fn g_file_replace_contents_bytes_async(
    file: *mut GFile,
    contents: *mut GBytes,
    etag: *const c_char,
    make_backup: gboolean,
    flags: GFileCreateFlags,
    cancellable: *mut GCancellable,
    callback: GAsyncReadyCallback,
    user_data: gpointer
)