public Shard getShardById(final int shardId) {
    return shardMap.get(shardId);
  }
@Test
  void testGetShardById() {
    var shard = new Shard(1);
    shardManager.addNewShard(shard);
    var tmpShard = shardManager.getShardById(1);
    assertEquals(shard, tmpShard);
  }