code: public SignalServiceMessagePipe createMessagePipe() {
      WebSocketConnection webSocket = new WebSocketConnection(urls.getSignalServiceUrls()[0].getUrl(),
                                                              urls.getSignalServiceUrls()[0].getTrustStore(),
                                                              Optional.of(credentialsProvider), userAgent, connectivityListener,
                                                              sleepTimer);
  
      return new SignalServiceMessagePipe(webSocket, Optional.of(credentialsProvider));
    }
docs: Creates a pipe for receiving SignalService messages.
  
  Callers must call {@link SignalServiceMessagePipe#shutdown()} when finished with the pipe.
  
  @return A SignalServiceMessagePipe for receiving Signal Service messages.