[Qemu-block] Fuzzing event loops

[Stefan Hajnoczi]

I wanted to share this idea about fuzzing event loops:

https://blog.acolyer.org/2017/06/09/node-fz-fuzzing-the-server-side-event-driven-architecture/

The idea is to expose ordering dependencies and atomicity bugs in
event loop callbacks/coroutines by randomly shuffling the order in
which fd handlers, timers, etc execute.

I'm not sure we'd find many bugs since QEMU tends to use big locks or
request serialization when concurrency gets tricky in the block layer.
Still, it's an interesting concept that we could apply in the future.

Stefan