Library Removes waitUrl Attribute When Set to Empty String Contrary to Documentation (<Conference> TwiML)

[vlad-tokarev]

Issue Summary

In the library, when setting the waitUrl attribute of a Conference TwiML conference to an empty string ('') to prevent any playback while waiting for the conference to start, the attribute is unexpectedly removed from the rendered TwiML. This behavior is inconsistent with the official documentation, which states that setting waitUrl to an empty string should be a valid option for achieving no playback during the wait period.

Steps to Reproduce

1. Run Code snippet
2. Check console output

Code Snippet

package main

import (
	"fmt"
	"github.com/twilio/twilio-go/twiml"
)

func main() {
	twimlConference := twiml.VoiceConference{
		Name:                "MyConference",
		WaitUrl: "",
	}

	voice, err := twiml.Voice([]twiml.Element{twimlConference})
	if err != nil {
		panic(err)
	}

	fmt.Printf("%s", voice)
}

Exception/Log

<?xml version="1.0" encoding="UTF-8"?><Response><Conference>MyConference</Conference></Response>

Technical details:

• twilio-go version: v1.17.0
• go version: 1.21

[tiwarishubham635]

I can look into this