@Override
  public void shutdown() {
    logger.info("Shutting down Http2BlockingChannelPool.");
    try {
      eventLoopGroup.shutdownGracefully().await(http2ClientConfig.http2BlockingChannelPoolShutdownTimeoutMs);
    } catch (InterruptedException e) {
      logger.info("EventLoopGroup shutdown timeout: {} ms",
          http2ClientConfig.http2BlockingChannelPoolShutdownTimeoutMs);
    }
  }
A connection pool that uses {@link Http2MultiplexedChannelPool} as the underlying channel for communication.
{@link Http2MultiplexedChannelPool} maintains physical connections to a host:port.
A stream channel represented by {@link Http2BlockingChannel} is checked out when checkOutConnection() is invoked.
ambry-network/src/main/java/com/github/ambry/network/http2/Http2BlockingChannelPool.java