It Max

seq := func(yield func(int) bool) {
    _ = yield(5)
    _ = yield(2)
    _ = yield(8)
    _ = yield(1)
    _ = yield(9)
}
max := it.Max(seq)
// max == 9

seq := func(yield func(string) bool) {
    _ = yield("zebra")
    _ = yield("apple")
    _ = yield("banana")
}
max := it.Max(seq)
// max == "zebra" (lexicographically largest)