Some things we can check and log plugin-error warnings (or even throw exceptions) for:

- metrics in the report are a subset of the metrics that were requested 
- the MeasurementScheduleRequests fields in the XxxDataXxx objects in the report are equivalent objects to the ones that were passed to the plugin's getValues() method
- metrics in the report have the correct data type - e.g. if a numeric metric named "foo" was requested, make sure the report contains a numeric metric "foo", and not a trait "foo" or call-time metric "foo".
- the report's collectionTime field has not been modified by the plugin - this field really should not even be exposed by the plugin API...