code: public void addHttp2ClientChannel(EventLoop eventLoop, HttpRoute httpRoute, Http2ClientChannel http2ClientChannel) {
          if (!eventLoops.contains(eventLoop)) {
              eventLoops.add(eventLoop);
          }
          final EventLoopPool eventLoopPool = getOrCreateEventLoopPool(eventLoop);
          String key = generateKey(httpRoute);
          final EventLoopPool.PerRouteConnectionPool perRouteConnectionPool = getOrCreatePerRoutePool(eventLoopPool, key);
          perRouteConnectionPool.addChannel(http2ClientChannel);
  
          // Configure a listener to remove connection from pool when it is closed
          http2ClientChannel.getChannel().closeFuture().
              addListener(future -> {
                              EventLoopPool.PerRouteConnectionPool pool = eventLoopPool.fetchPerRoutePool(key);
                              if (pool != null) {
                                  pool.removeChannel(http2ClientChannel);
                                  http2ClientChannel.getDataEventListeners().
                                      forEach(Http2DataEventListener::destroy);
                              }
                          }
              );
      }
docs: Add a given {@link Http2ClientChannel} to the relevant pool.
  
  @param eventLoop          netty event loop
  @param httpRoute          http route
  @param http2ClientChannel newly created http/2 client channel