private void addToPool(SessionProtocol actualProtocol, PoolKey key, PooledChannel pooledChannel) {
        assert eventLoop.inEventLoop() : Thread.currentThread().getName();
        getOrCreatePool(actualProtocol, key).addLast(pooledChannel);
    }
Adds a {@link Channel} to this pool.
core/src/main/java/com/linecorp/armeria/client/HttpChannelPool.java