code: protected static String[] getFileSystemCounterNames(String uriScheme) {
      String scheme = uriScheme.toUpperCase();
      return new String[]{scheme+"_BYTES_READ",
                scheme+"_BYTES_WRITTEN",
                scheme+"_FILES_CREATED",
                scheme + "_BYTES_READ_LOCAL",
                scheme + "_BYTES_READ_RACK",
                scheme + "_READ_EXCEPTIONS",
                scheme + "_WRITE_EXCEPTIONS"};
    }
docs: Counters to measure the usage of the different file systems.
  Always return the String array with two elements. First one is the name of
  BYTES_READ counter and second one is of the BYTES_WRITTEN counter.