about gogoprotobuf on slice when len = 0

gistfile1.txt

type A struct {
 slice []int
}

a = &A{make([]int, 0)}

bytes, _ := a.Marshal()

b := new(A) // b.slice == nil
b.Unmarshal(bytes)

re := reflect.DeepEqual(a, b) // re == false, because b.slice == nil, but a.slice != nil