v3 -> v4

Messaging Callbacks

v3

const inboundCallback: InboundMessageCallback = new InboundMessageCallback();
const sendingCallback: MessageSendingCallback = new MessageSendingCallback();
const deliveredCallback: MessageDeliveredCallback = new MessageDeliveredCallback();
const failedCallback: MessageFailedCallback = new MessageFailedCallback();

v4

const messageCallback: MessageCallback = new MessageCallback();