Jonathan Halliday

> If our goal is to provide a route into marshallers, maybe we should create a write-only API that facilitates this use-case Marshallers read an object model and transform it...

> If our Marshaller exposed a "write only API" to the producer of the profile, then the marshaller can do with the data as it will. There doesn't need to...

In term of relocating this to the same place the marshallers will eventually be, how about: `exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/data` or `exporters/profiles-otlp/src/main/java/io/opentelemetry/exporter/profiles/otlp/data`

> I think the lack of being able to reference attributes by index is a problem, but otherwise this seems like a good start. Yes, I think we've reached the...