The order determines the maximum output but you can also use the duration to set the withinDuration optional value to make sure you get one recent event from all three sources. If the incoming event stream is at 5, 10 and 15 seconds you can set the withinDuration to 15 seconds to produce an outbound event that will have the most recent 5 and 10 second events tied to the 15 second event.
This probably makes more sense as it keeps the readings in context. Otherwise your application should take into account that you will have 5 second readings paired with the old 10 and 15 second readings and you will only have an up-to-date reading from all three sources once every 3 events.
The order determines the maximum output but you can also use the duration to set the withinDuration optional value to make sure you get one recent event from all three sources. If the incoming event stream is at 5, 10 and 15 seconds you can set the withinDuration to 15 seconds to produce an outbound event that will have the most recent 5 and 10 second events tied to the 15 second event.
This probably makes more sense as it keeps the readings in context. Otherwise your application should take into account that you will have 5 second readings paired with the old 10 and 15 second readings and you will only have an up-to-date reading from all three sources once every 3 events.