code: boolean addAndCheckIfReady(int event) {
          int b = bits.addAndGet(event);
          boolean isReady = b == READY_WITHOUT_SIGNAL || b == READY_WITH_UNNECESSARY_SIGNAL || b == READY_WITH_SIGNAL;
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
              Tr.debug(this, tc, "addAndCheckIfReady " + event + ", polling state: " + b + ", " + isReady);
          return isReady;
      }
docs: Add an event and then check if we are ready for polling.
  
  @param event an event such as SERVER_STARTED or SIGNAL_RECEIVED
  @return true if ready for polling. Otherwise false.