I'm a bit confused by the documentation of ExactSizeIterator. As far as I understand, the **only** think I need to do it to implements the functions `iter()`

and `size_hint()`

when implementing `Iterator`

. `size_hint()`

should return `(exact_size, Some(exact_size))`

with `exact_size`

being the exact number of elements that will be yielded.

The `len()`

function doesn't need to be implemented and will just use `size_hint().0`

=> Is this right, because the example implements `len()`

and not `size_hint()`

.