Shiny 1.2.0: Plot caching

This is a companion discussion topic for the original entry at

We’re pleased to announce the CRAN release of Shiny v1.2.0! This release features Plot Caching, an important new tool for improving performance and scalability in Shiny apps.
If you’re not familiar with the term “caching”, it just means that when we perform a time-consuming operation, we save (cache) the results so that the next time that operation is requested, we can skip the actual operation and instantly fetch the previously cached results.