(fix): polling retry-after

(tests): polling rate-limit

(doc): changelog update

tgapi/errors.go

@@ -1,6 +1,9 @@
 package tgapi
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
 // ErrPoolUnexpected reports an unexpected result type returned from the worker pool.
 var ErrPoolUnexpected = errors.New("unexpected response from pool")
@@ -10,3 +13,18 @@ var ErrPoolQueueFull = errors.New("worker pool queue full")
 
 // ErrPoolStopped reports that a request was submitted after the worker pool stopped.
 var ErrPoolStopped = errors.New("worker pool stopped")
+
+// ResponseError reports an unsuccessful Telegram API response.
+type ResponseError struct {
+	Code        int
+	Description string
+	Parameters  *ResponseParameters
+}
+
+// Error returns the Telegram API error code and description.
+func (e *ResponseError) Error() string {
+	if e == nil {
+		return "<nil>"
+	}
+	return fmt.Sprintf("[%d] %s", e.Code, e.Description)
+}