code: public ClientSocket openSticky()
    {
      State state = _state;
      if (! state.isSessionEnabled()) {
        return null;
      }
  
      ClientSocket stream = openRecycle();
  
      if (stream != null)
        return stream;
  
      long now = CurrentTime.currentTime();
  
      if (isFailed(now)) {
        return null;
      }
  
      if (isBusy(now)) {
        return null;
      }
  
      return connect();
    }
docs: Open a stream to the target server for a session.
  
  @return the socket's read/write pair.