Gets the resource associated with the client-side appointment by its index.
GetResource(index: number): string
An integer, representing an index of a resource in a resource collection associated with the current appointment.
An identifier of the specified resource (IPersistentObject.Id)
If the AppointmentStorageBase.ResourceSharing is false, only one resource can be associated with a particular appointment.
Use the ASPxClientAppointment.AddResource method to add resources to the collection associated with the client appointment.