code: func (wfe *WebFrontEndImpl) sendError(response http.ResponseWriter, logEvent *web.RequestEvent, prob *probs.ProblemDetails, ierr error) {
  	wfe.stats.httpErrorCount.With(prometheus.Labels{"type": string(prob.Type)}).Inc()
  	web.SendError(wfe.log, probs.V2ErrorNS, response, logEvent, prob, ierr)
  }
docs: // sendError wraps web.SendError