Add manual/public Free method about gocroaring

[Oppen]

What should happen if I try to operate on a Free'd bitmap? panic? Or do we just expect the user to write correct code that doesn't attempt that?

[lemire]

I think that we expect the users to write correct code. You'd have to go out of your way to write a manual free. You should know what you are doing at that point.

[Oppen]

I'm having trouble coming up with an automated test that goes beyond smoke testing. I've been able to corroborate manually freeing reduces peak memory usage compared to relying on finalizers by using the time tool, but since the Go MemStats only track what the runtime knows about I can't show a thing in the tests themselves.
Any ideas?

[willglynn]

Well, here's an idea. Make a test function that go runs a subprocess, syscall.Getrusage() to measure its RSS? That'd parallelize with the rest of the test harness and would limit the memory measurements to just the code in question.

[Oppen]

Cool, I like that.