Struct holding a reference to a Deno runtime NIF resource.

This is an opaque value managed internally by Tyrex — you should not create or modify it directly.

The :reference field is the opaque NIF resource handle (a Rustler ResourceArc) that keeps the underlying Deno worker alive for as long as this struct is reachable. Dropping the struct without a matching Tyrex.stop/1 lets the resource be garbage-collected, which best-effort signals the worker to shut down.