chore(docs): add to readme

README.md

@@ -2,10 +2,11 @@
 
 A modernized set of node metrics for OpenTelemetry. Based on two excellent modules:
 
-* [Marc Bachmann's opentelemetry-node-metrics](https://github.com/marcbachmann/opentelemetry-node-metrics)
-* [Simon Nyberg's prom-client](https://github.com/siimon/prom-client)
+- [Marc Bachmann's opentelemetry-node-metrics](https://github.com/marcbachmann/opentelemetry-node-metrics)
+- [Simon Nyberg's prom-client](https://github.com/siimon/prom-client)
 
 Usage:
+
 ```sh
 yarn add @sesamecare-oss/opentelemetry-node-metrics
 ```
@@ -21,3 +22,5 @@ setupNodeMetrics(meter);
 ```
 
 Now your Prometheus-exported metrics should be included along with whatever other metrics you ahve selected. See [openapi-typescript-infra/service](https://github.com/openapi-typescript-infra/service) for a more complete example of metrics integrated with an express service host.
+
+One notable change from the existing libraries - they divide active handles and active 'requests' using deprecated Node APIs. I've chosed to merge these into 'resources' using the new getActiveResourcesInfo API, which is Node17+. It should fail gracefully if that function is not available.