The [Usage for the Schedule resource](https://www.medplum.com/docs/api/fhir/resources/schedule?section=usage) refers to Timing, but [this page](https://www.hl7.org/fhir//api/fhir/datatypes/timing) 404s and I don't see it in the FHIR Resources. What is the best practice for storing the delivery of a medication? Thanks!