Consider adding a way to retrieve the OperationName from a ISpan

[paulomorgado]

If I have an ISpan instance, I can set it's operation name. But I can't retrieve it.

[austinlparker]

The specification doesn't indicate having the operation name being a property that can be read, true. What is your proposed use case?

[austinlparker]

For background, there was some discussion about this same issue in the Java lib - opentracing/opentracing-java#285

[paulomorgado]

I find it strange that I can set the operation name on a span whenever I want to, but cannot read it. The same for tags, by the way.

If I were to design this API, I would have a read-only property for the operation name and no API to change it.

I was trying to feed the span to the logger and get the operation name from it but, no luck.