I'm looking for some recommendations on the best ways to test layer load performance via the 4.x jsapi. We are trying to document the differences in load times between AGOL vs our hosted map services. My initial speculation is that a good way to go would be using the 'before-add' and 'after-add' events on the map.layers collection. Are those events specific to adding an item to a collection (just increasing the length of the list by one), or would they also capture the time needed to fetch a layer and load it in the map?
Is there a better way / place to measure the time needed to fetch the layer and add it to a map?