OpenTelemetry SDK exporters that write spans, log records and metrics into the telemetry model, so that the telemetry of a unit of work is saved as models next to the models it describes, with recorded model changes in the spans that made them. The Nasdanika Zephyr Book of the telemetry model and its exporters, "Telemetry Model", is built from src/docs/asciidoc with listings from the tests.