@Override
    public boolean remove(PooledConnection conn) {
        if (conn == null) {
            return false;
        }
        if (!conn.isInPool()) {
            return false;
        }

        // Get the eventloop for this channel.
        EventLoop eventLoop = conn.getChannel().eventLoop();

        // Attempt to remove connection from the pool.
        Deque<PooledConnection> connections = getPoolForEventLoop(eventLoop);
        if (connections.remove(conn)) {
            conn.setInPool(false);
            connsInPool.decrementAndGet();
            return true;
        } else {
            return false;
        }
    }
function to run when a connection is acquired before returning it to caller.
zuul-core/src/main/java/com/netflix/zuul/netty/connectionpool/PerServerConnectionPool.java