Subscription: keep alive publish response send late after last notification data
The subscription mechanism complies with the OPC UA specification part4 v1.03 but it leads to unexpected behavior on keep alive publish responses. The keep alive publish response after a data change notification is 1 publishing expiration late, whereas it is correct between 2 keep alive publish responses (see maxKeepAliveCount
value configured in CreateSubscription service).
See https://apps.opcfoundation.org/mantis/view.php?id=5367.
The goal is to have the expected behavior for all keep alive publish responses, i.e. on maxKeepAliveCount
publishing expiration(s) without notification a keep alive message shall be sent.