Function pointer type for add-on provided functions that allow the user to be notified when externally-owned data is ready to be cleaned up because the object with which it was associated with, has been garbage-collected. The user must provide a function satisfying the following signature which would get called upon the object’s collection. Currently, napi_finalize can be used for finding out when objects that have external data are collected.

    1. typedef void (*napi_finalize)(napi_env env,
    2.                               void* finalize_data,
    3.                               void* finalize_hint);

    Unless for reasons discussed in [Object Lifetime Management][], creating a handle and/or callback scope inside the function body is not necessary.