adding support for setting the status of the span through SpanExt

[webfinesse]

Motivation

I have found that when working with tracing spans created by 3rd party libraries, it is incredibly difficult to set the OpenTelemetry Status of the span, which results in always having an unset span in my visualization tool.

In this case, I am working with the span created by the aws_lambda_runtime crate.

Unfortunately, since the span in the aws_lambda_runtime crate does not include the otel.status_code attribute upfront the OpenTelemetryLayer::SpanAttributeVisitor::record_str and OpenTelemetryLayer::SpanAttributeVisitor::record_debug never gets triggered when calling tracing::Span::current().record("otel.status_code", "ok"); This behavior of the record function ignoring new fields is documented here

Solution

My solution to this is add a new member OpenTelemetrySpanExt::set_status that takes an opentelemetry::trace::Status enum that gets written to the underlying SpanBuilder.

[djc]

This makes sense to me, thanks!

(In addition to my remarks below, need to fix up the formatting to appease CI.)