Speeding up Leaflet-based Shiny Apps with Polygon Simplification

Optimizing the performance of Shiny applications has a number of sub-topics that deserve attention. One particular class of applications that we've observed significant performance issues are those that involve the use of interactive maps with polygons overlaid from shapefiles. An example of this type of application can be seen in our Bullying Application. This map draws a Leaflet map and overlays shapes representing the school districts in the state of Iowa (as of 2016):