Possible bug in Async.flatten

[MrMage]

According to https://github.com/vapor/core/blob/master/Sources/Async/Future%2BFlatten.swift, "the order of the results will match the order of the futures in the input array.". But the current implementation simply adds an awaiter to each future, which appends its result to the final result array. That means that elements actually get appended in the order in which the futures are fulfilled, not in the order the futures had in the input array.

[tanner0101]

That is a bug, thank you for finding that @MrMage. We used to have an orderedFlatten and non ordered flatten. It looks like the docs for orderedFlatten got applied here incorrectly. I think the best solution here is to make this actually do an ordered flatten.