docs: public void sendMessage(Message message)
      {
          if (message == null)
              return;     // Don't allow a null message to be sent.
          m_stack.add(message);
          if (m_bWaiting)
          {
              synchronized (m_thread)
              {
                  if (m_bWaiting) // Inside the sync block
                      m_thread.notify();
              }
          }
      }