message: save one PacketHeader copy in QuicHeaderCodec
  Summary: create the temp obj inline
diff: @@ -34,9 +34,10 @@ folly::Expected<ParsedHeaderResult, TransportErrorCode> parseHeader(
  }
  // We compensate for the type byte length by adding it back.
  DCHECK(parsedLongHeaderResult.parsedLongHeader);
  - auto parsedHeader = PacketHeader(
  - std::move(parsedLongHeaderResult.parsedLongHeader->header));
  - return ParsedHeaderResult(false, parsedHeader);
  + return ParsedHeaderResult(
  + false,
  + PacketHeader(
  + std::move(parsedLongHeaderResult.parsedLongHeader->header)));
  });
  } else {
  return parseShortHeader(initialByte, cursor).then([](ShortHeader&& header) {
  