添加NetworkErr

client.go

@@ -74,6 +74,9 @@ func (c *Client) do(req *http.Request) (*http.Response, error) {
 		hook.BeforeRequest(req)
 	}
 	resp, err := c.Client.Do(req)
+	if err != nil {
+		err = NetworkErr{error: err}
+	}
 	for _, hook := range c.HttpHooks {
 		hook.AfterRequest(resp, err)
 	}

items.go

@@ -240,3 +240,14 @@ type PushLoginResponse struct {
 func (p PushLoginResponse) Ok() bool {
 	return p.Ret == "0" && p.UUID != ""
 }
+
+type NetworkErr struct{ error }
+
+func (n NetworkErr) Unwrap() error {
+	return n.error
+}
+
+func IsNetworkError(err error) bool {
+	_, ok := err.(NetworkErr)
+	return ok
+}