@SuppressWarnings("GuardedBy")
    @Override
    public String toString() {
        final List<Endpoint> endpoints = endpoints();
        final List<Endpoint> delegateEndpoints = delegate.endpoints();
        return MoreObjects.toStringHelper(this)
                          .add("endpoints", truncate(endpoints, 10))
                          .add("numEndpoints", endpoints.size())
                          .add("candidates", truncate(delegateEndpoints, 10))
                          .add("numCandidates", delegateEndpoints.size())
                          .add("selector", toStringSelector())
                          .add("initialized", whenReady().isDone())
                          .add("initialSelectionTimeoutMillis", initialSelectionTimeoutMillis)
                          .add("selectionTimeoutMillis", selectionTimeoutMillis)
                          .add("contextGroupChain", contextGroupChain)
                          .toString();
    }
Returns a newly-created {@link MeterBinder} which binds the stats about this
{@link HealthCheckedEndpointGroup}.
core/src/main/java/com/linecorp/armeria/client/endpoint/healthcheck/HealthCheckedEndpointGroup.java