Retrieve a collector of a specific type by address, creating a new one if it does not exist.
Retrieve a collector of a specific type by address, creating a new one if
it does not exist. If an existing collector of a different type already
exists, a DuplicateMetricException
will be thrown.
Address meant to be relative to this MetricNamespace's namespace
Function which takes in an absolutely pathed MetricAddress, and a CollectorConfig and returns an instance of a Collector