title: Weird Blocked thread warnings
body: <p>We are running a spring boot vertx application in an OpenShift cluster.
  Using vertx 4.2.3 and spring boot 2.6.2.
  The application listens for incoming tcp connections and forward messages to rabbit mq
  We have lowered the time limit for warning about blocked thread to 500 ms</p>
  <p>We are getting a number of warnings like this</p>
  <pre><code>Thread Thread[vert.x-eventloop-thread-1,5,main] has been blocked for 1250 ms, time limit is 500 ms
  io.vertx.core.VertxException: Thread blocked
      at java.base@17.0.1/sun.nio.ch.EPoll.wait(Native Method)
      at java.base@17.0.1/sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:118)
      at java.base@17.0.1/sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:129)
      at java.base@17.0.1/sun.nio.ch.SelectorImpl.select(SelectorImpl.java:141)
      at io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62)
      at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:817)
      at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:460)
      at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)
      at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
      at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
      at java.base@17.0.1/java.lang.Thread.run(Thread.java:833)
  </code></pre>
  <p>As this doesn't include any of our code in the stack trace. we have a hard time understanding what is wrong. We are with ZGC garbage collector and do not see any unusual GC pause times.</p>
  <p>Any ideas?</p>