Exception in thread "vertx-blocked-thread-checker" java.util.ConcurrentModificationException
	at java.util.WeakHashMap$HashIterator.nextEntry(WeakHashMap.java:806)
	at java.util.WeakHashMap$KeyIterator.next(WeakHashMap.java:839)
	at io.vertx.core.impl.BlockedThreadChecker$1.run(BlockedThreadChecker.java:45)
	at java.util.TimerThread.mainLoop(Timer.java:555)
	at java.util.TimerThread.run(Timer.java:505)