private Set<Category> getCategorySet(String[] categories) {
    return Stream.of(categories).map(String::toLowerCase).map(Category::valueOf)
        .collect(Collectors.toSet());
  }
Gets the metrics of region on a given member

@return ResultData with required Region statistics or ErrorResultData if Region MBean is not
        found to gather metrics
geode-gfsh/src/main/java/org/apache/geode/management/internal/cli/commands/ShowMetricsCommand.java