docs: public Http2HeadersStreamSinkChannel createInitialUpgradeResponseStream() {
          if (lastGoodStreamId != 0) {
              throw new IllegalStateException();
          }
          lastGoodStreamId = 1;
          Http2HeadersStreamSinkChannel stream = new Http2HeadersStreamSinkChannel(this, 1);
          StreamHolder streamHolder = new StreamHolder(stream);
          streamHolder.sourceClosed = true;
          currentStreams.put(1, streamHolder);
          receiveConcurrentStreamsAtomicUpdater.getAndIncrement(this);
          return stream;
  
      }