suggest iterator.count() instead of iterator.collect<Vec<_>>.len()

[matthiaskrgr]

instead of doing something like

let len = iterator.collect<Vec<_>>.len();

we might want to suggest

let len = iterator.count();

however, .count() consumes the iterator so I am not sure if this is always applicable.

[shssoichiro]

+1, this should always be safe if .collect().len() is done inline--the intermediate collected data structure is guaranteed to never be reused in this case.

[shssoichiro]

I'll go ahead and pick this up.