private void launchAdditionalThread(Runnable r, ThreadPoolExecutor executor) {
      Thread th = executor.getThreadFactory().newThread(r);
      th.start();
    }
Handle rejected execution for a function execution thread. Spin off a thread directly in
this case, since that means a function is executing another function. The child function
request shouldn't be in the queue behind the parent request since the parent function is
dependent on the child function executing.
geode-core/src/main/java/org/apache/geode/distributed/internal/FunctionExecutionPooledExecutor.java