将依赖事件总线的发布订阅模式，改为直接调用的形式

common/Tnb.Common/Extension/TaskExtensions.cs

@@ -25,6 +25,21 @@ namespace Tnb.Common.Extension
             return tcs.Task;
         }
 
+        public static async Task<T> Retry<T>(Func<Task<T>> task, int retries,     
+                                TimeSpan delay, CancellationToken cts = default) =>
+            await task().ContinueWith(async innerTask =>
+            {
+                cts.ThrowIfCancellationRequested();
+                if (innerTask.Status != TaskStatus.Faulted)
+                    return innerTask.Result;
+                if (retries == 0)
+                    throw innerTask.Exception ?? throw new Exception();
+                await Task.Delay(delay, cts);
+                return await Retry(task, retries - 1, delay, cts);
+            }).Unwrap();
+
+
+
         public static async Task Catch(this Task task, Func<Exception,Task> exceptionHandler)
         {
             try