ELF: On reduce, hop to target EventLoop before doing operation (#1070)
ELF: On reduce, hop to target EventLoop before doing operation (#1070)

Motivation:

Folds often involves chaining multiple futures together. It's
beneficial if you're already on the target EventLoop as it might
vastly reduce the amount of EventLoop hops.

Modifications:

Execute onto the target EventLoop before doing the folds.

Result:

Fixes #1054
apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio