startChildSpan with SpanOptions interface only.

[mayurkale22]

Continuation of #484, this PR is to cleanup and match internal interfaces with top level APIs. i.e. Internal startChildSpan interface accepts same argument(SpanOptions) as public facing Tracer's startChildSpan.

This PR does not contain any breaking change.

[mayurkale22]

/cc @hekike FYI.

[codecov-io]

Codecov Report

Merging #521 into master will decrease coverage by 0.51%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #521      +/-   ##
==========================================
- Coverage   95.27%   94.75%   -0.52%     
==========================================
  Files         147      147              
  Lines       10808    10491     -317     
  Branches      907      911       +4     
==========================================
- Hits        10297     9941     -356     
- Misses        511      550      +39

Impacted Files	Coverage Δ
src/detect-resource.ts	60% <0%> (-30.91%)	⬇️
test/test-http2.ts	77.83% <0%> (-18.99%)	⬇️
src/common-utils.ts	95.83% <0%> (-4.17%)	⬇️
src/tags/propagation/variant-encoding.ts	96% <0%> (-4%)	⬇️
test/test-instana.ts	85.18% <0%> (-3.71%)	⬇️
test/test-jaeger-format.ts	95.38% <0%> (-1.8%)	⬇️
test/test-detect-resource.ts	97.43% <0%> (-1.71%)	⬇️
src/tags/propagation/binary-serializer.ts	95.58% <0%> (-1.52%)	⬇️
src/trace/model/no-record/no-record-span.ts	57.53% <0%> (-0.91%)	⬇️
test/test-ioredis.ts	97.16% <0%> (-0.55%)	⬇️
... and 35 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1a77de1...622b401. Read the comment docs.

[draffensperger]

What's the role of the brackets [ ] around options in the JSDoc? Does that signify that it's optional?

[mayurkale22]

Yes, brackets are used to indicate optional param.

[hekike]

Thanks for cleaning it up!

[hekike]

Should we add these to the changelog update?

[mayurkale22]

Should we add these to the changelog update?

I thought about it, but as this is an internal interface change I didn't include in CHANGELOG. WDYT?

[hekike]

Hmm, technically you can require @opencensus/core which exports types: https://github.com/census-instrumentation/opencensus-node/blob/master/packages/opencensus-core/src/index.ts#L19 But I don't feel strong about it.

[mayurkale22]

Yeah, this is a valid point. I will update the CHAGELOG. Thanks