当我的[] byte在GO中的长度为零时，如何通过准备好的语句在postgres bytea列中插入NULL？

I am using following function inside my prepared statements for inserting NULL for zero values of type string and int64 but I can not find way to insert null when my []byte array is of zero length.

Golang Insert NULL into sql instead of empty string

// NewNullString converts empty string into db NULL
func NewNullString(s string) sql.NullString {
  if len(s) == 0 {
    return sql.NullString{}
  }
  return sql.NullString{
    String: s,
    Valid:  true,
  }
}

// NewNullInt64 converts 0 int64 into db NULL
func NewNullInt64(i int64) sql.NullInt64 {
   if i == 0 {
    return sql.NullInt64{}
   }
  return sql.NullInt64{
    Int64: i,
    Valid: true,
   }
}