code: public void sendContextControlMessage(final EvaluatorRuntimeProtocol.ContextControlProto contextControlProto) {
      synchronized (this.evaluatorDescriptor) {
        LOG.log(Level.FINEST, "Context control message to {0}", this.evaluatorId);
        this.contextControlHandler.send(contextControlProto);
      }
    }
docs: Packages the ContextControlProto in an EvaluatorControlProto and forward it to the EvaluatorRuntime.
  
  @param contextControlProto message contains context control info.