It Repeatby

result := it.RepeatBy(3, func(index int) string {
    return fmt.Sprintf("item-%d", index+1)
})
var output []string
for item := range result {
    output = append(output, item)
}
// output contains ["item-1", "item-2", "item-3"]

result2 := it.RepeatBy(5, func(index int) int {
    return index * 2
})
var output2 []int
for item := range result2 {
    output2 = append(output2, item)
}
// output2 contains [0, 2, 4, 6, 8]