Can I implement `TrustedLen` for wrapper of `Iter` and `BitValIter`?

[YjyJeff]

I am using bitvec in my own project. I need the iterator that implement the TrustedLen in my API, such that I can do some optimization. Can I implement the TrustedLen for the wrapper of Iter and BitValIter?

AFAIK, I can do it. BitPtrRange knows the accurate length. Am I right?

Thanks in advance!