如何检测interface {}是否为指针？

I'm wondering how can you know if the interface is of type pointer.

package main

import "fmt"
import "reflect"

type str struct {
    a, b string
}

func main() {
    var s str
    x := &s
    t := reflect.TypeOf(interface{}(x))
    fmt.Printf("%v", t.Size())
}

Use a type switch if you already know the type(s):

switch v.(type) {
case *str:
    return "*str"
case str:
    return "str"
}

If you don't, then you can use if reflect.TypeOf(v).Kind() == reflect.Ptr {}

playground