I don't know why author thinks that blocking IO is a "One of the most frustrating things when you start with go" because from the very beginning of leaning Go m

I don't know why author thinks that blocking IO is a "One of the most frustrating things when you start with go" because from the very beginning of leaning Go most articles, tutorials and books tells that golang uses goroutines to achieve concurrency. I've started learning golang a few weeks ago and the fact that all IO is blocking was the most nicest part of the language. I mean you dont need to wrap your code in deeply nested callbacks as you do in node.js, and your code is always look straightforward. In fact IO is only looks blocking, AFAIK, go uses epoll/kqueue under the hood for IO operations.