try {
      reader =
          (ShuffleReader<K, C>)
              delegate
                  .getClass()
                  .getDeclaredMethod(
                      "getReader",
                      ShuffleHandle.class,
                      int.class,
                      int.class,
                      int.class,
                      int.class,
                      TaskContext.class,
                      ShuffleReadMetricsReporter.class)
                  .invoke(
                      handle,
                      startMapIndex,
                      endMapIndex,
                      startPartition,
                      endPartition,
                      context,
                      metrics);
    } catch (Exception e) {
      throw new RssException(e);
    }