Don't know if subscribed to event with DeepstreamClient.event.subscribe

[mannyhappenings]

DeepstreamClient.event.subscribe() takes eventName and listener to event but doesn't take subscription callback, i.e., I don't know if after calling this function I will receive events or not.

Or is it that this function will return only after subscription.

I can see the line "Subscribes to eventName and notifies the listener via EventListener whenever it occurs locally or remotely." on page but not sure how to use it to check subscription on client side.