code: func (h *httpStreamHandler) hasStreamPair(requestID string) bool {
  	h.streamPairsLock.RLock()
  	defer h.streamPairsLock.RUnlock()
  
  	_, ok := h.streamPairs[requestID]
  	return ok
  }
docs: // hasStreamPair returns a bool indicating if a stream pair for requestID
  // exists.