protected static String sizeToString(final long size) {
    if (size >= (1L << 50)) {
      return String.format("%.2fP", (double) size / (1L << 50));
    }
    if (size >= (1L << 40)) {
      return String.format("%.2fT", (double) size / (1L << 40));
    }
    if (size >= (1L << 30)) {
      return String.format("%.2fG", (double) size / (1L << 30));
    }
    if (size >= (1L << 20)) {
      return String.format("%.2fM", (double) size / (1L << 20));
    }
    if (size >= (1L << 10)) {
      return String.format("%.2fK", (double) size / (1L << 10));
    }
    return String.format("%.2fB", (double) size);
  }
Called by toSetQuotaRequestProto() the subclass should implement this method to set the
specific SetQuotaRequest properties.
hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaSettings.java