Yes, this particular raster is quite small, only a few megs, and loads fairly quickly when displayed as a raster image with the addRasterImage() function. I posted it merely as an example of the underlying javascript.
But I hope to display global extent data that is several gigs in its native format in a Shiny app, and I understand this far is beyond the capacity of addRasterImage(). The leaflet documentation advises against anything larger than 8 megs. The native format of the raster data is .tif, but the link I provided earlier is the product of a tiling process that has transformed these data into 256x256 pixel .pngs at various zoom levels, and indexed them such that they can be accessed in the Google Maps API. This process was conducted in Google Earth Engine, for those that are wondering, and I have no idea how that operation was performed.
I'm hoping that there is a way to to access these tiles in leaflet to rapidly display global high resolution imagery and at the same time benefit from the ease of interactivity provided in Shiny. Is there a way to do this with the addTiles() function in leaflet?