An experiment for adding transparent zipkin tracing capabilities to akka. Transparent in this context means no modifications to existing Actor/ActorRef/Message implementations. Also it avoids using java agent instrumentation. "Business code" (actors/messages) should remain as is (without tracing API dependency) Only extensions and custom ActorSystem(s) are allowed.

See Zipkin Issue 450 for discussion details.

This is work in progress and API is unstable.