refactoring

src/DotNetCore.CAP/IQueueExecutor.Subscribe.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Diagnostics;
 using System.Threading.Tasks;
+using DotNetCore.CAP.Abstractions;
 using DotNetCore.CAP.Infrastructure;
 using DotNetCore.CAP.Internal;
 using DotNetCore.CAP.Models;

src/DotNetCore.CAP/Processor/IProcessor.Failed.cs

@@ -1,8 +1,7 @@
 using System;
-using System.Collections.Generic;
 using System.Threading.Tasks;
+using DotNetCore.CAP.Abstractions;
 using DotNetCore.CAP.Infrastructure;
-using DotNetCore.CAP.Internal;
 using DotNetCore.CAP.Models;
 using DotNetCore.CAP.Processor.States;
 using Microsoft.Extensions.DependencyInjection;