3.1.5.2 AsyncNotify Pending Timer Event
If the server implements version 2 of the protocol, it MUST implement this timer event.
When the Notification Pending Timer (section 3.1.2.2) expires, the server MUST search for the WitnessRegistration entry in WitnessRegistrationList. If WitnessRegistration.IsAsyncNotifyRegistered is TRUE and WitnessRegistration.LastUseTime plus WitnessRegistration.KeepAliveTime is earlier than the current time, the server MUST fail the request with ERROR_TIMEOUT.