Event loop is of course good thing... when it possible. But it isn't always possible: sometimes I need to do very long calculations inside event loop and this will result in FDs timeout and error.
Also event loop isn't good idea if "process IO buffer" isn't main task of this program.

Threads... hmm... not in perl. At least - not current iThreads. They are too slow and use too much memory.

So I wonna to make safe ASYNC IO without threads using SIGNALS as was described before.