code: private void setUp() throws Exception {
      try {
        fileSystem = (DistributedFileSystem) FileSystem.get(
            StorageServiceConfigKeys.translateToOldSchema(conf, nameserviceId), conf);
        InetSocketAddress nameNodeAddr = fileSystem.getClient().getNameNodeAddr();
        metaInfo = new RequestMetaInfo(clusterId, nameserviceId, RequestMetaInfo.NO_NAMESPACE_ID,
            RequestMetaInfo.NO_APPLICATION_ID, (UnixUserGroupInformation) UserGroupInformation.getUGI(
            this.conf));
  
        directClientProtocol = RPC.getProxy(ClientProtocol.class, ClientProtocol.versionID,
            nameNodeAddr, conf);
  
        directClientProxyProtocol = RPC.getProxy(ClientProxyProtocol.class,
            ClientProxyProtocol.versionID, nameNodeAddr, conf);
  
        clientManager = new ThriftClientManager();
        FramedClientConnector connector = new FramedClientConnector(HostAndPort.fromParts(
            proxyHostname, proxyPortThrift));
        proxyTClientProxyProtocol = clientManager.createClient(connector, TClientProxyProtocol.class)
            .get();
  
        proxyClientProxyProtocol = RPC.getProxy(ClientProxyProtocol.class,
            ClientProxyProtocol.versionID, new InetSocketAddress(proxyHostname, proxyPortRPC), conf);
  
        fileSystem.mkdirs(new Path(ROOT));
      } catch (Exception e) {
        tearDown();
        throw e;
      }
    }
docs: Sets up clients before each benchmark