Production-ready accept loop handling

[tailhook]

I've just published a PR to add the chapter on writing accept loops to the async-std book. Since this is a real problem for a lot of current Rust applications (including for web frameworks like tide), I want to bring more attention to the topic in the Rust community. Adding it to rust async book should help.

More background: async-std issue and older tokio issue.

I'd like to add something similar to the async-book. But few questions first:

1. The work on the book looks like inactive for now. Is it alive, or basically it's split into "async-std book" and "tokio book"?
2. Do we need a section on async-std?
3. Should the issue here have the same level of detail that it has in async book PR?
4. Any guidelines on how to share the problem statement between async-std and tokio sections in this book (if we are going to add them here)?

Or any other guidelines that could be helpful....