docs: public static Deferred<Annotation> getAnnotation(final TSDB tsdb, 
        final byte[] tsuid, final long start_time) {
      
      /**
       * Called after executing the GetRequest to parse the meta data.
       */
      final class GetCB implements Callback<Deferred<Annotation>, 
        ArrayList<KeyValue>> {
  
        /**
         * @return Null if the meta did not exist or a valid Annotation object if 
         * it did.
         */
        @Override
        public Deferred<Annotation> call(final ArrayList<KeyValue> row) 
          throws Exception {
          if (row == null || row.isEmpty()) {
            return Deferred.fromResult(null);
          }
          Annotation note = JSON.parseToObject(row.get(0).value(),
              Annotation.class);
          return Deferred.fromResult(note);
        }
        
      }
  
      final GetRequest get = new GetRequest(tsdb.dataTable(), 
          getRowKey(start_time, tsuid));
      get.family(FAMILY);
      get.qualifier(getQualifier(start_time));
      return tsdb.getClient().get(get).addCallbackDeferring(new GetCB());    
    }