code: func ValidateIncomingRequest(host string, authToken string, req *http.Request) (err error) {
  	err = req.ParseForm()
  	if err != nil {
  		return
  	}
  	err = validateIncomingRequest(host, authToken, req.URL.String(), req.Form, req.Header.Get("X-Twilio-Signature"))
  	if err != nil {
  		return
  	}
  
  	return
  }
docs: // ValidateIncomingRequest returns an error if the incoming req could not be
  // validated as coming from Twilio.
  //
  // This process is frequently error prone, especially if you are running behind
  // a proxy, or Twilio is making requests with a port in the URL.
  // See https://www.twilio.com/docs/security#validating-requests for more information