UNSTABLE: Unsafe and new API, beware!
The function pointer remains valid until the
close() method is called.
The callback can be explicitly ref'ed and deref'ed to stop Deno's process from exiting.
Removes the C function pointer associated with the UnsafeCallback. Continuing to use the instance after calling this object will lead to errors and crashes.
Calling this method will also immediately set the callback's reference counting to zero and it will no longer keep Deno's process from exiting.
Adds one to this callback's reference counting.
If the callback's reference count becomes non-zero, it will keep Deno's process from exiting.