OpenTelemetry RxJava & OkHttp+Retrofit libraries generate isolated spans on Rx rescheduling

[ponomarevlm]

Jaeger is used for visualisation.

Describe the bug
When I configure OkHttp client as described here and then use it with Retrofit and it's RxJava2CallAdapterFactory.createWithScheduler(Schedulers.io()) which reschedules calls, spans are isolated. With a custom tracing assembly (see below) they are linked.

Steps to reproduce

    fun retrofit() {
        tracer.spanStart("retrofit") {
            api.query()
                .andThen(api.error())
                .doOnTerminate { it.end() }
                .subscribe({/* ignore */ }, {/* swallow */ })
        }
    }

Full demo source can be found here

What did you expect to see?
Chained okhttp+retrofit+rx calls should be linked to parent

What did you see instead?
For retrofit spans are not linked together:

What version are you using?
opentelemetry-api:1.24.0
opentelemetry-rxjava-2.0:1.24.0-alpha
opentelemetry-okhttp-3.0:1.24.0-alpha

Environment
Compiler: Android Studio Embedded JDK 11.0.15
OS: macOS 12.2 Monterey
Runtime: Android 10 ART
OS: Android 10

Additional context
I have tried to move context capturing to on*Assembly with custom tracing assembly. It works a bit better standalone or with stock, at least it gathers retrofit chains (see retrofit expectations illustration), but it breaks tests when ported into stock.

[trask]

@ponomarevlm (some of the) folks in this repo (me) aren't very android savvy, can this be reproduced as a standalone Java app?

[trask]

hi @ponomarevlm, I think we would need a standalone repro that we can easily run in order to debug and understand this issue, is that something you could provide?