Adding layers beneath labels

[ianthetechie]

It would be nice to be able to idiomatically expose an API for attempting to do this.

My assumption is that labels generally need to be on top of almost everything else, and they tend to be grouped together. Further, the default behavior you want for most overlays is to put them directly below the labels.

Ideally we could add a LayerInsertionPosition variant belowLabels which carries the intent to add the layer below the first label layer after looping sequentially through all current layers.