程序集： Microsoft.ServiceBus（在 Microsoft.ServiceBus.dll 中）
The sequence number is scoped to the queue or topic. The value is only available on the message received from the Service Bus.
For queues, sequence numbers are assigned to each message in ascending order. For topics and subscriptions, the sequence number for every subscription starts at 1. Therefore, if you create a new subscription, SequenceNumber is set to 1, but applies to the new message that was published after the subscription was created.