Hi Matthew
In the In-Queue Flow there is a built in system variable you can use for Estimated Wait time, Call.EstimatedWaitTime, which you can then check against a duration you choose.
If you are looking to do this outside of the In-Queue Flow, or you want to specifically use average wait time instead, then you will need to use a Data Action to get the wait time from the aggregate analytics api, and then check against that instead.
Or if you want to only after a certain wait, just add up the music time, announcement time etc, and then after the right amount of time has passed then offer the callback
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Anton Vroon
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