Consider adopting ECS convention for logging spec's Trace Context in Legacy Formats

[trask]

Currently, the logging spec's Trace Context in Legacy Formats says:

the following field names should be used in legacy formats:

"trace_id" for TraceId, hex-encoded.
"span_id" for SpanId, hex-encoded.
"trace_flags" for trace flags, formatted according to W3C traceflags format.

I think it's worth considering using instead the ECS field names trace.id, span.id and trace.flags.

Related: open-telemetry/opentelemetry-java-instrumentation#7985

cc @AlexanderWert

[dashpole]

Is this issue still being considered? I see elastic/ecs-logging-java#214 (comment), #3469, and #3518 suggest we are planning to keep the current field names.

I'm interested in seeing https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/compatibility/logging_trace_context.md reach stability, and this appears to be the only related issue.

@jack-berg @tigrannajaryan

[tigrannajaryan]

I think the conclusion in #3518 was that we keep the names. It has been a while and there is no new evidence that we need to do something else so I suggest that we submit a PR that declares https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/compatibility/logging_trace_context.md "Stable" and closes this issue.
@dashpole do you want to do it?

[dashpole]

PR: #3909

[svrnm]

@open-telemetry/technical-committee please take a look, the PRs related to this have been auto-closed, is this something that is done or that needs additional attention?