anchor.diff:  
   [NOTE]
   ====
  -If you are already using a Zipkin server capturing trace information from multiple platform/frameworks, you also use a https://cloud.google.com/trace/docs/zipkin[Stackdriver Zipkin proxy] to forward those traces to Stackdriver Trace without modifying existing applications.
  +If you are already using a Zipkin server capturing trace information from multiple platform/frameworks, you can also use a https://cloud.google.com/trace/docs/zipkin[Stackdriver Zipkin proxy] to forward those traces to Stackdriver Trace without modifying existing applications.
   ====
   
   === Tracing
  
positive.code: == Spring Cloud Sleuth
  
  https://cloud.spring.io/spring-cloud-sleuth/[Spring Cloud Sleuth] is an instrumentation framework for Spring Boot applications.
  It captures trace informations and can forward traces to services like Zipkin for storage and analysis.
  
  Google Cloud Platform provides its own managed distributed tracing service called https://cloud.google.com/trace/[Stackdriver Trace].
  Instead of running and maintaining your own Zipkin instance and storage, you can use Stackdriver Trace to store traces, view trace details, generate latency distributions graphs, and generate performance regression reports.
  
negative.code: Since Stackdriver Trace doesn't support span joins, a new span ID is always generated, regardless of the one specified in `x-cloud-trace-context`.
  
  `TRACE_TRUE` can either be `0` if the entity should be untraced, or `1` if it should be traced.
  This field forces the decision of whether or not to trace the request; if omitted then the decision is deferred to the sampler.
  
  If a `x-cloud-trace-context` key isn't found, `StackdriverTracePropagation` falls back to tracing with the https://github.com/openzipkin/b3-propagation[X-B3 headers].
  
  