add exception class.

src/DotNetCore.CAP/Internal/MethodBindException.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace DotNetCore.CAP.Internal
+{
+    [Serializable]
+    public class MethodBindException : Exception
+    {
+        public MethodBindException() { }
+        public MethodBindException(string message) : base(message) { }
+        public MethodBindException(string message, Exception inner) : base(message, inner) { }     
+    }
+}