constructor(opts, registry) {
		this.registry = registry;
		this.type = opts.type;
		this.name = opts.name;
		this.description = opts.description;
		this.labelNames = opts.labelNames || [];
		this.unit = opts.unit;
		this.aggregator = opts.aggregator || registry.opts.defaultAggregator;

		this.lastSnapshot = null;
		this.dirty = true;

		this.values = new Map();
	}
Creates an instance of BaseMetric.

@param {Object} opts
@param {MetricRegistry} registry
@memberof BaseMetric