Field names for v3 recommendation

[nrktkt]

Over on the JSON-RPC mailing list we've been discussing a trace context format for JSON-RPC. We were planning to use "traceparent" and "tracestate" as the field names on the outermost JSON object. If we go with a simple string format, that means that for JSON-RPC over MQTT, values injected by MQTT implementations would be readable by JSON-RPC implementations. Which would be cool, but dangerous if a JSON-RPC implementation on the sending side sets those fields only to have them overwritten by the MQTT implementation.

My recommendation would be at a minimum to add to your recommendation specifying that those fields must not be overwritten if they are present in the original payload, and possibly to update the recommendation with more collision resistant field names like "__traceparent" or "tcmqtt_traceparent".

PS. I'm sorry that discussion requires a google account to read the conversation, that's a distasteful change to groups.