Provide a `collectIndexed` terminal operator

Hi,

Like with collections and sequences we occasionally need to iterate and maintain an index like this:

var index = 0
values.collect {
  // do something with the value, knowing its index.
  ++index
}

Since forEachIndexed already exists for Iterable and Sequence and consumeEachIndexed exists for ReceiveChannel it would seem natural to me that flows provide a collectIndexed terminal operator.

[elizarov]

@jcornaz When you say “we occasionally need” can you provide a slightly more concrete example where this might be needed when you work with flows, please. E.g. if you had recently run into this need in your project, you can explain what was the problem you were solving.

[fvasco]

@jcornaz

I’d call it withIndex()

I agree.

it does not need to wrap each value

In escape analisys we hope