All modules that uses Coro will segfault if You try to use them. After talking to author of Coro You will learn that it is a feature - not a bug.
a code that is written by not stupid human usually says that there is not enough memory (a example). Coro, EV, etc prefer to crash (segfault) instead usually behavior: You can waste a lot of time to understand that the library requires to do something against to read normal error report.
So I join one previous review: "Author is not very nice"
but don't join that: "the module is great".
code that segfaults if You try to step to the left or the right from example can't be great.
I've found a few troubles: all they were fixed immediately or in short time period.
Author always responses, adds test for each issue comment etc.
The module has many unresolved memory leaks. I've discussed (I sought a version without the problem) the question in a few maillists (for ex. email@example.com) there are a lot of people say there that memory leak is a permanent property of the module.
Also the module has unfinished async mode. You cannot process a few operations in non-blocking mode, for example: connect. It's a pity that such low level driver is in such oppressing status.