Notes on Python asyncio

You choose to live with the extra complexity of asynchronous I/O (aka event-driven) almost always only for scaling up the number of concurrent connections.

Python 3 provides an asyncio package on a provisional basis. It has a pluggable event loop and separates transport from protocol. Python’s yield from makes asynchronous I/O moderately easier to code (but you will be punished for omitting yield from where you shouldn’t).

Question: Is it possible (i.e., easier than a rewrite) for a codebase to start with synchronous I/O and later switch to asynchronous I/O when it hits scaling issues? (I guess no.)