To include in a CompletableFutures item

Things to remember when writing a "Consider completable futures for coarse grained parallelism" item:

• A lot of effort has gone into making ForkJoinPool.commonPool() robust in the face of a wide variety of common usages, so it's normally safe to use the default asynchronous execution facility when setting up interdependent asynchronous tasks. However, if you ...
• The asynchronous execution indicated by the Async suffix on a method name refers to the returned CompletableFuture.
• CompletableFutures represent tasks, but the class extends CompletableStage, so the documentation uses the term "stage" everywhere, which can be confusing. Get in the habit of translating the word "stage" or "CompletableStage" to "task" in your head when reading these docs.