ReadonlyapplicationReadonlycontentThe upload's own content type (logging_client_events's form or the reliability log's multipart).
ReadonlydeviceReadonlyprofileReadonlyviewerThe signed-in viewer's id; undefined in a process with no viewer.
The caller-written headers of one Android system HTTP stack's request, in the order and the spelling the app sets them (
spec/transport-ownership.md, "The telemetry uploads beside Pigeon";packages/android/src/telemetry/spec/). The transport writes the stack's own headers around this list —Transfer-Encoding: chunked(for a body of writes) beforeHost,Connection,Accept-Encoding, andContent-Lengthlast — and refuses a caller header of one of those names, so the set below holds only what the caller owns.The order is the wire's, not a preference: a system stack writes the caller's headers as given. Each stack's set:
mqtt-analytics(the FBNS client event log):Content-Type,User-Agent(the MQTT analytics engine's),X-FB-HTTP-Engine: MQTT Analytics;urlconnection(the reliability log):User-Agent: Android,Content-Type, the viewer'sCookie(absent in a process with no signed-in viewer),X-FB-Request-Analytics-Tagswith the product alone.