This snippet aims to show how the `check` phase relates to `setTimeout(0)`. What does it print, and why is the order between `immediate` and `timeout` deterministic *here* but not when the same two are scheduled from the main module top level?
const fs = require('fs');
fs.readFile(__filename, () => {
setTimeout(() => console.log('timeout'), 0);
setImmediate(() => console.log('immediate'));
});