Support publishing W3C Trace Context in Kafka header

[Knappek]

When a frontend application sends a message to RIG, it can also send W3C Trace Context in the HTTP header and RIG will accept it and consume it. RIG will then read the Trace-ID, will create a new span based on this Trace-ID and optionally forward it to a distributed tracing system like Jaeger or OpenZipkin.

The issue now: This trace ends at this point.

Feature Request: RIG should forward the Trace Context to Kafka by putting it to the Kafka header. Then a backend system can consume the Trace Context. Additonally, if a backend system publishes messages to Kafka with Trace Context in the header, RIG should be able to read the Trace Context from the Kafka header.

Question: How do we deal with Kinesis or Nats, that do not have the concept of a header?