Clarify that IsValid and IsRemote are APIs on SpanContext

[bogdandrutu]

Signed-off-by: Bogdan Drutu bogdandrutu@gmail.com

Updates #753

Changes

Clarifies that IsValid and IsRemote are APIs.

[Oberon00]

I know I missed that we had IsValid (#753), but I think this was my mistake. It is actually clear enough in the spec already IMHO. If we add headings for IsValid and IsRemote, we should also add headings for SpanId, TraceId, TraceFlags, TraceState, and that would be a lot of headings.

[bogdandrutu]

They will come because there is an issue about format of trace id / span id formats that we expose. Tried to keep PRs small :)

[Oberon00]

I'm approving because I don't want to have this hanging in the air and I don't think it's making the spec worse, but I think the clarification is not really needed either.

[bogdandrutu]

Trivial change, don't have to wait 48h :)

[obecny]

I think that this information (isValid) is kind of duplicate and redundant. if this "api" is meant to return true only if spanId and traceId are valid what is really the purpose of keeping this extra information on context - this sounds for me like really redundant thing. This information can be simply checked by some helper function so no reason to keep it on context. WDYT ?

[arminru]

@obecny The spec does not specify how it should be implemented but I'm pretty sure the intended way is indeed exposing a helper function checking spanId and traceID just as you mentioned rather than storing an actual flag.