Heartbeat values sent have same sourceTimestamp and serverTimestamp as LKV

[marcschier]

In 2.8 heartbeat values had sourceTimestamp and serverTimestamp different from the LKV allowing counting distinct values. This issue is to create backwards compatibility with 2.8 by faking timestamp to be different than LKV.

[marcschier]

To count distinct values you can use "--fm=True" or use the Timestamp of the dataset message which will have a distinct value if "--mts=CreatedTimeUtc" is used (2.9.2) forward. Changing source timestamp or server timestamp is wrong as it implies these were provided by the underlying OPC Server this way (there is no heartbeat indicator). While heartbeat is sent the value could be different but not yet sampled.

[marcschier]

Added new --hbb=WatchdogLKVWithUpdatedTimestamps which tries to mimic 2.8.