关于golang:go变量

package mainimport (    "fmt"    "reflect"    "unsafe")func main() {    var s1, s2 string    var sh1, sh2 *reflect.StringHeader    s1 = "abcd"    s2 = s1    sh1 = (*reflect.StringHeader)(unsafe.Pointer(&s1))    fmt.Println(sh1.Data, sh1.Len, &s1)    sh2 = (*reflect.StringHeader)(unsafe.Pointer(&s2))    fmt.Println(sh2.Data, sh2.Len, &s2)    s2 = "cdef123"    sh2 = (*reflect.StringHeader)(unsafe.Pointer(&s2))    fmt.Println(sh2.Data, sh2.Len, &s2)}