设计了流程接口节点，能够切换本节点数据、目标节点数据，目前还有数据来源相关操作没有实现

Library/Api/IDynamicFlowNode.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Serein.Library.Api
@@ -11,6 +12,7 @@ namespace Serein.Library.Api
     /// </summary>
     public interface IDynamicFlowNode
     {
+        Task<FlowResult> ExecutingAsync(IDynamicContext context, CancellationToken token);
     }
 
 }