[Moving [discussion](https://github.com/akka/akka/pull/1152#discussion_r3098722) to new diff]

I was a bit confused by what the first two sentence meant. Maybe it was just the phrasing. Is the following kind of what you mean? If not, maybe you could try writing those sentences a different way so I can understand them. :)

"A method is synchronous if it blocks internally. A method that performs a CPU intensive task internally is also synchronous. It is considered synchronous because, despite not blocking internally, it still prevents the caller from making progress while it executes."