Method Peek

cpp/src/arrow/flight/serialization_internal.h:207–215

      : stream_(stream), peek_(), finished_(false), valid_(false) {}

  void Peek(internal::FlightData** out) {
    *out = nullptr;
    if (finished_) {
      return;
    }
    if (EnsurePeek()) {
      *out = &peek_;
    }
  }

  void Next(internal::FlightData** out) {
    Peek(out);