8.1.1 broke the Status callbacks

[marocano1]

The changes made in 8.1.1, specifically turning the nullable feature on, has broken the Status callbacks. Every property that does not have the nullable operator, (i.e. '?'), is now required.

Due to that, our status callback endpoint has been returning a 400 because the "Body" property on the SmsRequest class, which is the base class for the SmsStatusCallbackRequest class, is now required.

This is a breaking change that was introduced with 8.1.1. Can we please get a fix in for it as soon as possible?

[Swimburger]

You can make a copy of the class locally and fix it as a temporary fix.
Feel free to make a PR here too.

For now, making that field nullable would be the best fix.
However, longer term, we should consider not inheriting from VoiceRequest and SmsRequest for the callback classes.
Unfortunately, Twilio doesn't document their callbacks very well (callbacks issue OpenAPI), so the code in this repo is best effort based on their documentation.