@Override
  public boolean start() throws IOException {
    LOG.info("Starting reader using {}", initCheckpoint);
    try {
      shardSubscribersPool = createPool();
      shardSubscribersPool().start(initCheckpoint);
      return advance();
    } catch (TransientKinesisException e) {
      throw new IOException(e);
    }
  }
@Test
  public void startReturnsFalseIfNoDataAtTheBeginning() throws IOException {
    assertThat(reader.start()).isFalse();
  }