@Override
            public void failed(final Exception cause) {
                final AsyncDataConsumer entityConsumer = entityConsumerRef.getAndSet(null);
                if (entityConsumer != null) {
                    entityConsumer.releaseResources();
                }
                asyncExecCallback.failed(cause);
            }
Request execution handler in the asynchronous request execution chain
that is responsible for establishing connection to the target
origin server as specified by the current connection route.

@since 5.0
httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AsyncConnectExec.java