hide Publisher and Subscriber's getStats()

The methods are not yet implemented,
so there is no reason to expose it.
Another way out is to delete it for the time being.

Author: pongad

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/Publisher.java

@@ -467,8 +467,8 @@ public boolean failOnFlowControlLimits() {
     return failOnFlowControlLimits;
   }
 
-  /** Retrieves a snapshot of the publisher current {@link PublisherStats statistics}. */
-  public PublisherStats getStats() {
+  /** Retrieves a snapshot of the publisher current statistics. */
+  private PublisherStats getStats() {
     // TODO: Implement this.
     throw new UnsupportedOperationException();
   }

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/PublisherStats.java

@@ -23,7 +23,7 @@
  * Publisher}.
  */
 @AutoValue
-public abstract class PublisherStats {
+abstract class PublisherStats {
   /** Number of successfully published messages. */
   public abstract long getAckedMessages();
 

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/Subscriber.java

@@ -356,7 +356,7 @@ public void run() {
     }
   }
 
-  public SubscriberStats getStats() {
+  private SubscriberStats getStats() {
     // TODO: Implement me
     return null;
   }

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/SubscriberStats.java

@@ -23,8 +23,8 @@
  * Subscriber}.
  */
 @AutoValue
-public abstract class SubscriberStats {
-  
+abstract class SubscriberStats {
+
   @AutoValue
   //TODO: Finish implementation.
   public abstract static class Stats {}