MetricReader.groovy

@Override
T read() {
    namespace.push("read")
    def timer = metricRegistry.timer(namespace.name()).time()
    try {
        T result = delegate.read()
        if (result != null) timer.stop()
        result
    } catch (all) {
        metricRegistry.counter("${namespace}.error").inc()
        throw all
    } finally {
        namespace.pop()
    }
}