No span compression with apmotel

[milesich]

Describe the bug
When apmotel package is imported spans cannot be compressed.

apmotel package override the apm context functions which calls span.TraceContext which marks the trace context as propagated. One of the requirement for a span to be eligible for compression is that the context is not propagated.

To Reproduce
A simple example like the one here with apmotel package imported.

Expected behavior
Spam should be eligible for compression when apmotel package is imported.

[dmathieu]

There are actually two problems here:

As you mention, apmotel needs to call TraceContext() to properly propagate the span information, which marks the span as having been propagated and prevents compression.
Otel has no notion of "exit spans", so we can't mark OpenTelemetry spans as exit ones, so they will never be elligible for compression.