Options accepted when enqueueing a job.
Transport headers to carry with the job, delivered to the processor as
IJob.headers.
Delivery does NOT depend on which capabilities are registered: a map
passed here reaches the processor whether or not telemetry is present.
With a CAPABILITIES.TELEMETRY provider the framework ADDS a W3C
traceparent to whatever the caller supplied, so an enqueued job joins
the trace of the request that enqueued it.