Function gio_sys::g_file_replace_contents_async

pub unsafe extern fn g_file_replace_contents_async(file: *mut GFile,
                                                   contents: *mut u8,
                                                   length: size_t,
                                                   etag: *const c_char,
                                                   make_backup: gboolean,
                                                   flags: GFileCreateFlags,
                                                   cancellable: *mut GCancellable,
                                                   callback: GAsyncReadyCallback,
                                                   user_data: gpointer)