disable streaming thread

Author: sakthivelmanii

google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSetImpl.java

@@ -489,7 +489,8 @@ public ApiFuture<Void> setCallback(Executor exec, ReadyCallback cb) {
       // Start to fetch data and buffer these.
       this.result = SettableApiFuture.create();
       this.state = State.STREAMING_INITIALIZED;
-      this.service.execute(new InitiateStreamingRunnable());
+      initiateProduceRows();
+//      this.service.execute(new InitiateStreamingRunnable());
       this.executor = MoreExecutors.newSequentialExecutor(Preconditions.checkNotNull(exec));
       this.callback = Preconditions.checkNotNull(cb);
       pausedLatch.countDown();