There may be some pieces that are easily shared - so I've recently made a swift package (not yet versioned) that takes the proto files that represent the definitive models from OpenTelemetry, generates the swift for them, and makes the resulting "thing" available in a swift package.
The package is at https://github.com/heckj/OpenTelemetryModels - and usable, if very rough and bare bones - as it is. The current package maps to the OpenTelemetry spec v0.3.0, which was loosely pegged in the sand recently, and implements a concrete data model that aligns with the w3c trace content.
The downside of this particular package is that raw protobuf models are kind of awkward to deal with, so as I've been using the resulting package I'm making notes and helpers, and will be dragging/refactoring some of that back into that package to make it easier to work with the spans, events, traces, etc. I'm planning on getting it to where I feel like it's more minimally useful before calling it version "0.3.0" to match with the opentelemetry spec as it evolves.
If it helps someone else, then perfect - that's why I have it public in my repo.