@UnstableApi
    public static CloseableMeterBinder eventLoopMetrics(EventLoopGroup eventLoopGroup,
                                                        MeterIdPrefix meterIdPrefix) {
        return new EventLoopMetrics(eventLoopGroup, meterIdPrefix);
    }
Returns a new {@link MeterBinder} to observe Netty's {@link EventLoopGroup}s. The following stats are
currently exported per registered {@link MeterIdPrefix}.

<ul>
  <li>"event.loop.workers" (gauge) - the total number of Netty's event loops</li>
  <li>"event.loop.pending.tasks" (gauge)
    - the total number of IO tasks waiting to be run on event loops</li>
</ul>
core/src/main/java/com/linecorp/armeria/common/metric/MoreMeterBinders.java