High amounts of 'default I/O' threads in EAP 7+

Issue

• We see a high amount of default I/O threads in a state like below in JBoss EAP and they are never released:

"default I/O-1500" #1603 prio=5 os_prio=0 cpu=1.54ms elapsed=48347.33s tid=0x00007faeeca05800 nid=0x731 runnable  [0x00007faee0bf3000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.EPoll.wait(java.base@11.0.20/Native Method)
    at sun.nio.ch.EPollSelectorImpl.doSelect(java.base@11.0.20/EPollSelectorImpl.java:120)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(java.base@11.0.20/SelectorImpl.java:124)
    - locked <0x0000000502b92b18> (a sun.nio.ch.Util$2)
    - locked <0x0000000502b92ac0> (a sun.nio.ch.EPollSelectorImpl)
    at sun.nio.ch.SelectorImpl.select(java.base@11.0.20/SelectorImpl.java:141)
    at org.xnio.nio.WorkerThread.run(WorkerThread.java:532)