code: public static void helpQuiesce() {
          ForkJoinWorkerThread wt =
              (ForkJoinWorkerThread)Thread.currentThread();
          wt.pool.helpQuiescePool(wt.workQueue);
      }
docs: Possibly executes tasks until the pool hosting the current task
  {@link ForkJoinPool#isQuiescent is quiescent}. This method may
  be of use in designs in which many tasks are forked, but none
  are explicitly joined, instead executing them until all are
  processed.
  
  <p>This method may be invoked only from within {@code
  ForkJoinPool} computations (as may be determined using method
  {@link #inForkJoinPool}).  Attempts to invoke in other contexts
  result in exceptions or errors, possibly including {@code
  ClassCastException}.