Add trace headers to http subscriptions #1323

Job	Run time
setup	13s
validate-example (actor)	2m 9s
validate-example (configuration)	1m 20s
validate-example (conversation)	1m 39s
validate-example (crypto)	1m 8s
validate-example (dist-scheduler)	1m 6s
validate-example (grpc-service)	2m 10s
validate-example (hello-world)	46s
validate-example (pubsub)	2m 2s
validate-example (streamsub)	59s
validate-example (service)	1m 54s
validate-example (socket)	51s
validate-example (workflow)	1m 34s
validate-example (workflow-parallel)	1m 1s
	18m 52s

Provide feedback