Tracing modules will subclass #GstTracer and register through gst.tracer.Tracer.register. Modules can attach to various hook-types - see gst.global.tracingRegisterHook. When invoked they receive hook specific contextual data, which they must not modify.
Fluent builder for gst.tracer.Tracer
Fluent builder implementation template for gst.tracer.Tracer
Module for Tracer class