The Functions page only showed a plain function, so it never said where a class's `__init__` runs. Users loading a large model need to know it is not the client: registration reads the signature and ships the source.
This adds a section on class Functions: `__init__` runs once per instance on the worker, then `__call__` per row or batch and `close()` on retirement, state is per instance, and `__init__` parameters are initialization fields set per binding. The example's test asserts that registering the class does not construct it.
Wyatt Alt
b4cbaf2f67