getSubscriptionId method
The server-side unique persistent ID of the MPN subscription.
The ID is available only after the MPN subscription has been successfully subscribed on the server. I.e. when its status is SUBSCRIBED or
TRIGGERED.
Note: more than one MpnSubscription may exists at any given time referring to the same MPN subscription, and thus with the same subscription ID.
For instance, copying an MpnSubscription with the copy initializer creates a second MpnSubscription instance with the same subscription ID. Also,
the coalescing flag of LightstreamerClient.subscribe may cause the assignment of a pre-existing MPN subscription ID
to the new subscription.
Two MpnSubscription objects with the same subscription ID always represent the same server-side MPN subscription. It is the client's duty to keep the status
and properties of these objects up to date and aligned.
Lifecycle This method can be called at any time.
Returns the MPN subscription ID.
Implementation
external String? getSubscriptionId();