Interfaces
NotificationChannelInterface
The NotificationChannelInterface interface allows to implement a Notification Channel by implementing the sendNotificationMethod. This implementation will be invoked when a Notification is requested to be sent to the associated channel.
NotificationEnvelope sendNotification(NotificationEnvelope notificationEnvelope);
The sendNotification() method should ideally update the relevant fields in the NotificationEnvelope when returning it. For instance, the status and the externalId.