title Scenario 1. Worklist returns the long-running result through the publisher. 

participant Issuer
participant Assignee
participant Worklist
participant Publisher

note over Worklist:**activity-instance** topic is a channel that publishes messages related to changes in an activity instance.

Issuer-->Publisher:Subscribe **activity-instance** topic
Assignee-->Publisher:Subscribe **activity-instance** topic
Issuer->Worklist:Issue new activity
Issuer<-Worklist:Returns activity-instance-id
Worklist->Publisher:Dispatches that a new activity instance has been posted
Publisher-->Assignee:Notifies the assignee that a new activity instance has been assigned
Assignee->Worklist:Execute the activity-instance
Worklist->Publisher:Dispatch the result (activity-instance id, output result)
Publisher-->Issuer:Notify the result (activity-instance id, output result)
Publisher-->Assignee:Notify the result (activity-instance id, output result)