public Gauge declareGauge(String name, Point boundDimensions) {
        return declareGauge(name, Optional.ofNullable(boundDimensions), null);
    }
Declare a gauge metric, with default dimension values as given. Create
the point argument by using a builder from {@link #pointBuilder()}.

@param name the name of the metric
@param boundDimensions dimensions which have a fixed value in the life cycle of the metric object or null
@return a thread-safe gauge metric
container-core/src/main/java/com/yahoo/metrics/simple/MetricReceiver.java