Implement ContentStore
diff --git a/src/main/java/com/intel/jndn/utils/Subscriber.java b/src/main/java/com/intel/jndn/utils/Subscriber.java
index 4949826..89e5168 100644
--- a/src/main/java/com/intel/jndn/utils/Subscriber.java
+++ b/src/main/java/com/intel/jndn/utils/Subscriber.java
@@ -21,6 +21,11 @@
 /**

  * @author Andrew Brown, andrew.brown@intel.com

  */

-public interface Subscriber {

+public interface Subscriber extends AutoCloseable {

+  /**

+   * @param onMessage called every time a new message is received

+   * @param onError called every time an error occurs

+   * @return a cancellation token for stopping the subscription

+   */

   Cancellation subscribe(On<Blob> onMessage, On<Exception> onError);

 }