Enable setting SubscriptionName in EPiServer.Azure.Events.Internal.DefaultServiceBusEventProvider

Azure Servicebus has a rule that SubscriptionNames cannot be longer than 50 characters. Currently, SubscriptionName is set by the private field _uniqueName in DefaultServiceBusEventProvider.ctor() and there is no way to override it.

The field is set here:

public DefaultServiceBusEventProvider(AzureEventClientFactory clientFactory, EventsServiceKnownTypesLookup knownTypesLookup, IServiceBusSetup setup, AzureEventProviderOptions options)

{

...

_uniqueName = Environment.MachineName.Replace('/', '_').Replace(':', '_') + Guid.NewGuid().ToString("N");

...
}

Since SubscriptionName can only be 50 characters long and Guid.NewGuid().ToString("n") returns a 36 character long string, there is only 14 characters left for the MachineName.

A suggestion could be to have a SubscriptionName Setter in AzureEventProviderOptions.