disable streaming thread

Author: sakthivelmanii

google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockSpannerServiceImpl.java

@@ -651,6 +651,7 @@ private ByteString generateTransactionName(String session) {
       counter = new AtomicLong();
       transactionCounters.put(session, counter);
     }
+    System.out.printf("Generating session using Session ID %s\n", session);
     return ByteString.copyFromUtf8(
         String.format("%s/transactions/%d", session, counter.incrementAndGet()));
   }
@@ -1999,6 +2000,7 @@ private void ensureMostRecentTransaction(Session session, ByteString transaction
       if (index > -1) {
         long id = Long.parseLong(transactionId.toStringUtf8().substring(index + 1));
         if (id != counter.get()) {
+          System.out.printf("Session ID %s TransactionId %s\n", session.getName(), transactionId.toStringUtf8());
           throw Status.FAILED_PRECONDITION
               .withDescription(
                   String.format(