private Runnable watchForStop(BooleanSupplier stopCondition) {
    return () -> {
      while (!Thread.currentThread().isInterrupted() && !stopCondition.getAsBoolean()) {
      }
      stop();
    };
  }
Cancels all current running threads.
The thread pool remains open, and this contention service can be reused.
geode-junit/src/main/java/org/apache/geode/test/concurrent/CPUContentionService.java