static RequestInfo releaseAndCloseStreamChannel(Channel streamChannel) {
    logger.debug("Stream channel is being closed. Stream: {}, Parent: {}", streamChannel, streamChannel.parent());
    RequestInfo requestInfo = streamChannel.attr(Http2NetworkClient.REQUEST_INFO).getAndSet(null);
    if (requestInfo != null) {
      //REQUEST_INFO is used to indicate if a streamChannel has been released before.
      streamChannel.parent()
          .attr(Http2MultiplexedChannelPool.HTTP2_MULTIPLEXED_CHANNEL_POOL)
          .get()
          .release(streamChannel);
    }
    return requestInfo;
  }
This is a utility class used by HTTP2.
ambry-network/src/main/java/com/github/ambry/network/http2/Http2Utils.java