TCompactProtocol protocol id violation

[jspofford]

I was seeing a protocol id exception using TCompactProtocol with some complicated unit tests (multiple clients threads, complex thrift structures, variety of interactions). I fixed this issue by replacing "injected" with an integer level that follows structure nesting:
jspofford@e3b54db#diff-7571f63b5051b15d8bf04742cfc4e517

I would have submitted a pull request but had trouble reproducing in your simplified unit tests. I'd need to dig further to isolate how the stream position is being upset. You may want to include this change anyway simply to ensure that the span data is sent in the last field stop instead of the first one, assuming you want to measure until the end of the incoming data serialization instead of just the first structure.

Unit tests pass with this change.

[malafeev]

the reason why injected was added is to avoid multiple injections of span context in case of complex data structure.
@jspofford does level prevent it? Could you create PR (to avoid manual copy paste from you code)?
It would be great to have tests for your case (no rush :) )