Go の Map 関数はどのようにしてリスト要素の変換を効率化できるのでしょうか?

list = [1,2,3]
str = ', '.join(multiply(x, 2) for x in list)

list := []int{1,2,3}
list2 := []int

for _,x := range list {
    list2 := append(list2, multiply(x, 2))
}

str := strings.Join(list2, ", ")

func Map[T, V any](ts []T, fn func(T) V) []V {
    result := make([]V, len(ts))
    for i, t := range ts {
        result[i] = fn(t)
    }
    return result
}

input := []int{4, 5, 3}
outputInts := Map(input, func(item int) int { return item + 1 })
outputStrings := Map(input, func(item int) string { return fmt.Sprintf("Item:%d", item) })