Allows duplicating packets when requesting packet-in via PacketService

If false, the original packet is always sent to the controller.
If true, a copy of the packet is sent to the controller, as long as the packet can be duplicated.
If duplication is not supported, the original packet will be sent to the controller.

Change-Id: I566c799bb0afed03c3fae5815aa926b338cad953
diff --git a/core/api/src/main/java/org/onosproject/net/packet/PacketRequest.java b/core/api/src/main/java/org/onosproject/net/packet/PacketRequest.java
index 01116d8..2249102 100644
--- a/core/api/src/main/java/org/onosproject/net/packet/PacketRequest.java
+++ b/core/api/src/main/java/org/onosproject/net/packet/PacketRequest.java
@@ -28,28 +28,28 @@
 public interface PacketRequest {
 
     /**
-     * Obtain the traffic selector.
+     * Obtains the traffic selector.
      *
      * @return a traffic selector
      */
     TrafficSelector selector();
 
     /**
-     * Obtain the priority.
+     * Obtains the priority.
      *
      * @return a PacketPriority
      */
     PacketPriority priority();
 
     /**
-     * Obtain the application id.
+     * Obtains the application id.
      *
      * @return an application id
      */
     ApplicationId appId();
 
     /**
-     * Obtain the node id.
+     * Obtains the node id.
      *
      * @return an node id
      */
@@ -62,4 +62,11 @@
      */
     Optional<DeviceId> deviceId();
 
+    /**
+     * Obtains copy flag.
+     *
+     * @return true if copy flag is set
+     */
+    boolean copy();
+
 }