In order not to block the reactor I would like to read files asynchronously, but I've found no obvious way of doing it using EventMachine. I've tried a few different approaches, but none of them feels right:

• Just read the file, it'll block the reactor, but what the hell, it's not that slow (unless it's a big file, and then it definitely is).
• Open the file for reading and read a chunk on each tick (but how much to read? too much and it'll block the reactor, too little and reading will get slower than necessary).
• EM.popen('cat some/file', FileReader) feels really weird, but works better than the alternatives above. In combination with the LineAndTextProtocol it reads lines pretty swiftly.
• EM.attach, but I haven't found any examples of how to use it, and the only thing I've found on the mailing list is that it's deprecated in favour of…
• EM.watch, which I've found no examples of how to use for reading files.

How do you read files within a EventMachine reactor loop?