Adds a note about stop garbage collection

[arcanis]

I spent a good amount of time trying to figure out why the watch would randomly stop working (or not work at all within workers), until I stumbled upon this comment by @pipobscure in an unrelated thread.

Given that JS API don't generally have visible side effects on garbage collection, I think it's worth adding a very visible note 😅

[jakub-g]

This note is pretty important (spent a good amount of time wondering the same), could someone please review and merge it?

[jakub-g]

I'm wondering, maybe this note could be reflected in the sample code?
Something like:

const watchers = {};

const logAndWatch = (path) => {
    console.log('Watching ' + path)
    const stop = fsevents.watch(__dirname, (path, flags, id) => {
        const info = fsevents.getInfo(path, flags, id);
        console.dir(info);
    });
    watchers[path] = stop;
}

// Start observation and store the watcher
let myPath = '/path/to/somefile.txt';
logAndWatch(myPath);

// End observation, and get rid of the watcher
watchers[myPath]();
watchers[myPath] = null;

It's not as sweet as the original 4-liner, but can prevent some head scratching.

It seems inevitable to have to use an array or object to store the stop reference, otherwise in a local function the ref will go out of scope.