docs: def _makeHttpRequest(self, method, route, payload):
          """ Make an HTTP Request for the API endpoint.  This method wraps
          the logic about doing failure retry and passes off the actual work
          of doing an HTTP request to another method."""
  
          url = self._constructUrl(route)
          log.debug('Full URL used is: %s', url)
  
          hawkExt = self.makeHawkExt()
  
          # Serialize payload if given
          if payload is not None:
              payload = utils.dumpJson(payload)
  
          # Do a loop of retries
          retry = -1  # we plus first in the loop, and attempt 1 is retry 0
          retries = self.options['maxRetries']
          while retry < retries:
              retry += 1
              # if this isn't the first retry then we sleep
              if retry > 0:
                  time.sleep(utils.calculateSleepTime(retry))
              # Construct header
              if self._hasCredentials():
                  sender = mohawk.Sender(
                      credentials={
                          'id': self.options['credentials']['clientId'],
                          'key': self.options['credentials']['accessToken'],
                          'algorithm': 'sha256',
                      },
                      ext=hawkExt if hawkExt else {},
                      url=url,
                      content=payload if payload else '',
                      content_type='application/json' if payload else '',
                      method=method,
                  )
  
                  headers = {'Authorization': sender.request_header}
              else:
                  log.debug('Not using hawk!')
                  headers = {}
              if payload:
                  # Set header for JSON if payload is given, note that we serialize
                  # outside this loop.
                  headers['Content-Type'] = 'application/json'
  
              log.debug('Making attempt %d', retry)
              try:
                  response = utils.makeSingleHttpRequest(method, url, payload, headers)
              except requests.exceptions.RequestException as rerr:
                  if retry < retries:
                      log.warn('Retrying because of: %s' % rerr)
                      continue
                  # raise a connection exception
                  raise exceptions.TaskclusterConnectionError(
                      "Failed to establish connection",
                      superExc=rerr
                  )
  
              # Handle non 2xx status code and retry if possible
              status = response.status_code
              if status == 204:
                  return None
  
              # Catch retryable errors and go to the beginning of the loop
              # to do the retry
              if 500 <= status and status < 600 and retry < retries:
                  log.warn('Retrying because of a %s status code' % status)
                  continue
  
              # Throw errors for non-retryable errors
              if status < 200 or status >= 300:
                  data = {}
                  try:
                      data = response.json()
                  except Exception:
                      pass  # Ignore JSON errors in error messages
                  # Find error message
                  message = "Unknown Server Error"
                  if isinstance(data, dict):
                      message = data.get('message')
                  else:
                      if status == 401:
                          message = "Authentication Error"
                      elif status == 500:
                          message = "Internal Server Error"
                  # Raise TaskclusterAuthFailure if this is an auth issue
                  if status == 401:
                      raise exceptions.TaskclusterAuthFailure(
                          message,
                          status_code=status,
                          body=data,
                          superExc=None
                      )
                  # Raise TaskclusterRestFailure for all other issues
                  raise exceptions.TaskclusterRestFailure(
                      message,
                      status_code=status,
                      body=data,
                      superExc=None
                  )
  
              # Try to load JSON
              try:
                  return response.json()
              except ValueError:
                  return {"response": response}
  
          # This code-path should be unreachable
          assert False, "Error from last retry should have been raised!"