refactor(client): Simplfy async subscriptions (part 2)
refactor(client): Simplfy async subscriptions (part 2)

StalderT/open62541,JGrothoff/open62541,StalderT/open62541,StalderT/open62541,open62541/open62541,jpfr/open62541,jpfr/open62541,JGrothoff/open62541,JGrothoff/open62541,open62541/open62541,StalderT/open62541,open62541/open62541,open62541/open62541,jpfr/open62541,JGrothoff/open62541,jpfr/open62541