@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.HBCK)
  default Hbck getHbck() throws IOException {
    return FutureUtils.get(toAsyncConnection().getHbck());
  }
Retrieve an Hbck implementation to fix an HBase cluster. The returned Hbck is not guaranteed to
be thread-safe. A new instance should be created by each thread. This is a lightweight
operation. Pooling or caching of the returned Hbck instance is not recommended. <br>
The caller is responsible for calling {@link Hbck#close()} on the returned Hbck instance. <br>
This will be used mostly by hbck tool.
@return an Hbck instance for active master. Active master is fetched from the zookeeper.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/Connection.java