@Override
    public final O execute(ClientRequestContext ctx, I req) throws Exception {
        RequestMetricSupport.setup(ctx, REQUEST_METRICS_SET, meterIdPrefixFunction, false,
                                   successFunction != null ? successFunction::test
                                                           : ctx.options().successFunction(),
                                   distributionStatisticConfig);
        return unwrap().execute(ctx, req);
    }
Decorates a {@link Client} to collect metrics into {@link MeterRegistry}.
core/src/main/java/com/linecorp/armeria/client/metric/AbstractMetricCollectingClient.java