docs: def emit(self, action, payload):
          """Emit action with payload via `requests.post`."""
          url = self.get_emit_api(action)
          headers = {
              'User-Agent': 'rio/%s' % VERSION,
              'X-Rio-Protocol': '1',
          }
          args = dict(
              url=url,
              json=payload,
              headers=headers,
              timeout=self.timeout,
          )
          resp = requests.post(**args)
          data = resp.json()
          is_success = resp.status_code == 200
          result = dict(
              is_success=is_success,
              message=data['message'],
          )
          if result['is_success']:
              result.update(
                  event_uuid=data['event']['uuid'],
                  task_id=data['task']['id'],
              )
          return result