Generic extensions to the treatment API to support protocol extensions like
OF experimenter actions.

Change-Id: I88cc5896d17fdbf89807f911f9c23e4f19f6a5ad
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instruction.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instruction.java
index 2f6a1cc..31ad80c 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instruction.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instruction.java
@@ -92,7 +92,12 @@
         /**
          * Signifies that the traffic should be modified in L4 way.
          */
-        L4MODIFICATION
+        L4MODIFICATION,
+
+        /**
+         * Signifies that an extension instruction will be used.
+         */
+        EXTENSION
     }
 
     /**