Added ClientToken to ShadowDeltaUpdated (#263)

Author: TwistedTwigleg

samples/Shadow/src/main/java/shadow/ShadowSample.java

@@ -84,6 +84,9 @@ static void onShadowDeltaUpdated(ShadowDeltaUpdatedEvent response) {
         if (response.state != null && response.state.containsKey(SHADOW_PROPERTY)) {
             String value = response.state.get(SHADOW_PROPERTY).toString();
             System.out.println("  Delta wants to change value to '" + value + "'. Changing local value...");
+            if (!response.clientToken.isEmpty()) {
+                System.out.print("  ClientToken: " + response.clientToken + "\n");
+            }
             changeShadowValue(value);
         } else {
             System.out.println("  Delta did not report a change in " + SHADOW_PROPERTY);

sdk/src/main/java/software/amazon/awssdk/iot/iotshadow/model/ShadowDeltaUpdatedEvent.java

@@ -16,6 +16,13 @@
  */
 public class ShadowDeltaUpdatedEvent {
 
+    /**
+     * An opaque token used to correlate requests and responses.  Present only if a client token was used in the request.
+     *
+     */
+    public String clientToken;
+
+
     /**
      * The current version of the document for the device's shadow.
      *