@Override
    public void recordProxyRequestEnd() {
        concurrentRequests.decrementAndGet();
    }
Netty Origin basic implementation that can be used for most apps, with the more complex methods having no-op
implementations.

Author: Arthur Gonigberg
Date: December 01, 2017
zuul-core/src/main/java/com/netflix/zuul/origins/BasicNettyOrigin.java