code: def MakeRequest(self, data):
      
      stats_collector_instance.Get().IncrementCounter("grr_client_sent_bytes",
                                                      len(data))
  
      # Verify the response is as it should be from the control endpoint.
      response = self.http_manager.OpenServerEndpoint(
          path="control?api=%s" % config.CONFIG["Network.api"],
          verify_cb=self.VerifyServerControlResponse,
          data=data,
          headers={"Content-Type": "binary/octet-stream"})
  
      if response.code == 406:
        self.InitiateEnrolment()
        return response
  
      if response.code == 200:
        stats_collector_instance.Get().IncrementCounter(
            "grr_client_received_bytes", len(response.data))
        return response
  
      # An unspecified error occured.
      return response
docs: Make a HTTP Post request to the server 'control' endpoint.