Hub Connection Status 枚举
public enum IotHubConnectionStatus
The device or module is connected.
The client is connected, and ready to be used.
The device or module is disconnected.
Inspect the associated IotHubConnectionStatusChangeReason returned (and exception thrown, if any), and take appropriate action.
The device or module is attempting to reconnect.
The client is attempting to recover the connection. Do NOT close or open the client instance when it is retrying.