private static String name(final String... names) {
        final StringBuilder buf = StringBuilderHelper.get();
        for (final String name : names) {
            if (buf.length() > 0) {
                buf.append('_');
            }
            buf.append(name);
        }
        return buf.toString();
    }
Return the {@link Histogram} registered under this name; or create
and register a new {@link Histogram} if none is registered.
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/metrics/KVMetrics.java