Attribute	Attribute Meaning
total_count	Total cumulative number of missed deadlines detected for any instance read by the DataReader. Missed deadlines accumulate; that is, each deadline period the total_count will be incremented by one for each instance for which data was not received.
total_count_change	The incremental number of deadlines detected since the last time the listener was called or the status was read.
last_instance_handle	Handle to the last instance in the DataReader for which a deadline was detected.

The deadline that the DataReader was expecting through its QoS policy was not respected for a specific instance.