+ })
+ c.Transport = retry.Transport{
+ RoundTripper: c.Transport,
+ }
+
+ return c, nil
+}
+
+func (u *User) String() string {
+ return u.Email
+}
+
+func (u *User) Sign(payload string) string {
+ mac := hmac.New(sha1.New, []byte(u.ID))
+ mac.Write([]byte(payload))
+
+ return hex.EncodeToString(mac.Sum(nil))