code: public static void awaitGraphIndexUpdate(TitanGraph g, String indexName, long time, TemporalUnit unit) {
          awaitIndexUpdate(g,indexName,null,time,unit);
      }
docs: This method blocks and waits until the provided index has been updated across the entire Titan cluster
  and reached a stable state.
  This method will wait for the given period of time and throw an exception if the index did not reach a
  final state within that time. The method simply returns when the index has reached the final state
  prior to the time period expiring.
  
  This is a utility method to be invoked between two {@link com.thinkaurelius.titan.core.schema.TitanManagement#updateIndex(TitanIndex, com.thinkaurelius.titan.core.schema.SchemaAction)} calls
  to ensure that the previous update has successfully persisted.
  
  @param g
  @param indexName
  @param time
  @param unit