I wish there was an `Either` type in std. I realize that there used to be one and we have `Result` now. However, now that we have `impl Trait` it's worth revisiting, I believe. If we don't we'll have the one from `itertools`, the one from `futures` etc.
In most GCed languages it wouldn't matter so much because you'd return a boxed `Iterator` or `Future` or what have you. But in Rust you generally want to avoid the allocation.
In most GCed languages it wouldn't matter so much because you'd return a boxed `Iterator` or `Future` or what have you. But in Rust you generally want to avoid the allocation.