public static LocalMetrics createLocalMetrics(final boolean isEnabled) {
        return isEnabled
                ? new EnabledLocalMetrics()
                : DisabledLocalMetrics.INSTANCE;
    }
Creates a non-static {@link LocalMetrics} for transient use in a class/method.

@param isEnabled If false returns an instance that does nothing apart from call
                 the passed runnables/suppliers.
stroom-util/src/main/java/stroom/util/logging/SimpleMetrics.java