Paul Soares

I know Kotlin has different constraints, but subject and let are very valuable to remove boilerplate code. Just wanted to reference this as a potential feature. See: https://relishapp.com/rspec/rspec-core/v/3-9/docs/subject https://relishapp.com/rspec/rspec-core/v/3-9/docs/helper-methods/let-and-let

### Checklist - [X] The issue can be reproduced in the [auth0_flutter sample app](https://github.com/auth0-samples/auth0-flutter-samples/tree/main/sample) (or N/A). - [X] I have looked into the [Readme](https://github.com/auth0/auth0-flutter/tree/main/auth0_flutter#readme), [Examples](https://github.com/auth0/auth0-flutter/blob/main/auth0_flutter/EXAMPLES.md), and [FAQ](https://github.com/auth0/auth0-flutter/blob/main/auth0_flutter/FAQ.md) and have not...