fetch method

@override Future<ResponseBody> fetch(RequestOptions options, Stream<Uint8List>? requestStream, Future<void>? cancelFuture)

Implement this method to make real HTTP requests.

options are the request options.

requestStream is the request stream. It will not be null only when the request body is not empty. Use requestStream if your code rely on RequestOptions.onSendProgress.

cancelFuture corresponds to CancelToken handling. When the request is canceled, cancelFuture will be resolved. To await if a request has been canceled:

cancelFuture?.then((_) => print('request cancelled!'));

Implementation

@override
Future<ResponseBody> fetch(
  RequestOptions options,
  Stream<Uint8List>? requestStream,
  Future<void>? cancelFuture,
) async {
  if (_closed) {
    throw StateError(
      "Can't establish connection after the adapter was closed.",
    );
  }
  final operation = CancelableOperation.fromFuture(_fetch(
    options,
    requestStream,
    cancelFuture,
  ));
  cancelFuture?.whenComplete(() => operation.cancel());
  return operation.value;
}