init commit

Author: changliiu

sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/SpannerIO.java

@@ -522,6 +522,7 @@ public static Write write() {
    * change stream name.
    */
   public static ReadChangeStream readChangeStream() {
+    // changliiu starts here.
     return new AutoValue_SpannerIO_ReadChangeStream.Builder()
         .setSpannerConfig(SpannerConfig.create())
         .setChangeStreamName(DEFAULT_CHANGE_STREAM_NAME)