each_cons from Ruby in Swift as a function on Sequence

Array+EachCons.swift

extension Array {
    func eachConsecutive(_ n: Int) -> Array<ArraySlice<Iterator.Element>> {
        return (0..<(count-n+1)).map({ i in
            return self[i..<i+n]
        })
    }
}

Sequence+EachPair.swift

extension Sequence where SubSequence: Sequence, SubSequence.Iterator.Element == Iterator.Element {
    func eachPair() -> AnySequence<(Iterator.Element, Iterator.Element)> {
        return AnySequence(zip(self, self.dropFirst()))
    }
}