com.twitter.finagle.buoyant.linkerd.HttpTraceInitializer
Establish context for this request, as follows: 1.
Establish context for this request, as follows: 1. Set the trace id from the context header, if one was provided. 2. Get a new span id for the current request. 3. Use the sample header to determine if the request should be sampled.
Only set _sampled on the trace ID if the sample header provided a sample rate, the sampler determines that the request should be sampled based on the sample rate, and the _sampled field is unset on the current trace ID.