We want to follow what dataclass does and do model -> json serialization as a module-level method in azure.core.serialization. The thought here is to add something like model_dump in azure.core.serialization, which will take in a hybrid model and output it in a dumped model format. This way, people can save it to file / pass to json.dumps.

As part of this, we will deprecate .as_dict() on our new hybrid models