Invoke error handler when ctx.Done channel is closed

processor.go

@@ -203,6 +203,9 @@ func (p *processor) exec() {
 				return
 			case <-ctx.Done():
 				p.logger.Debugf("Retrying task. task id=%s", msg.ID) // TODO: Improve this log message and above
+				if p.errHandler != nil {
+					p.errHandler.HandleError(ctx, task, ctx.Err())
+				}
 				p.retryOrKill(ctx, msg, ctx.Err())
 				return
 			case resErr := <-resCh:

server.go

@@ -125,7 +125,7 @@ type Config struct {
 	ShutdownTimeout time.Duration
 }
 
-// An ErrorHandler handles errors returned by the task handler.
+// An ErrorHandler handles an error occured during task processing.
 type ErrorHandler interface {
 	HandleError(ctx context.Context, task *Task, err error)
 }