The Agent publishes incorrect timestamp sequences if the adapter streams with older data on connection

[simonyg]

During the Agent's startup, it marks all the data items with "Unavailable" and the current timestamp. On connecting to the agent, some adapter implementation could send older stale data to the agent. The agent will publish these data items with their older timestamps.

The sequence looks like this:

<now>,                    ItemId, Unavailable, 
<old time stamp>,         ItemId,  stale data
<next time stamp > now>,  itemId, new data

The Agent should always publish the data with forward timestamp. The expected behavior should be:

<now>,                    ItemId, Unavailable, 
<now+>,                   ItemId,  stale data
<next time stamp > now+>, itemId, new data

[wsobel]

I'll work a fix into the next release. I'm going to add a transform that does not allow time to go backwards.

[wsobel]

We will make this optional because some implementations require the original timestamps.

Creating ValidateTimestamps option in the agent. Default will be false.

[wsobel]

Should we ever allow timestamps in the future? This will cause an issue because any unavailable observation that is stamped now will happen before the future timestamp and cause it to be re-stamped (still before) the previous observation.

This all depends on how far in advance the observation is stamped.

Should this behavior always be stopped?

Change would force all observations to occur at or before now?