HTTPCLIENT-2231: a race condition in the main async exec when the request execution on an I/O thread is faster then execution pipeline management on the client thread

httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/HttpAsyncMainClientExec.java

@@ -133,8 +133,10 @@ class HttpAsyncMainClientExec implements AsyncExecChainHandler {
 
             @Override
             public void cancel() {
+                if (messageCountDown.get() > 0) {
                     failed(new InterruptedIOException());
                 }
+            }
 
             @Override
             public void produceRequest(