code: public String getClusterOrHostName() {
          if (StringUtils.isNotBlank(esConfig.getHostName()))
              return esConfig.getHostName();
          else
              return esConfig.getCluster();
      }
docs: Returns hostname that the benchmark will target if {@link IEsConfig#getHostName()}
  is defined, otherwise returns result of calling {@link IEsConfig#getCluster() }