private void shutdownSelectorIfIsSelector() {
    if (isSelector()) {
      hsTimer.cancel();
      if (tmpSel != null) {
        try {
          tmpSel.close();
        } catch (IOException ignore) {
        }
      }
      try {
        wakeupSelector();
        selector.close();
      } catch (IOException ignore) {
      }
      if (selectorThread != null) {
        selectorThread.interrupt();
      }
      commBufferQueue.clear();
    }
  }
Hand off a new client connection to the thread pool that processes handshakes. If all the
threads in this pool are busy then the hand off will block until a thread is available. This
blocking is good because it will throttle the rate at which we create new connections.
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/AcceptorImpl.java