Add support for debouncing filters

[Quazie]

I have an instance of react select with 4k items - searching, even with react-select-fast-filter-options feels real slow at first - it would be nice if searches themselves could be debounced to allow for better functionality with large lists of items.

[themre]

perhaps you can replace MenuList with react-window component? haven't tried it yet.

[axross]

Same here.

The reason why react-select slows down is not displaying results, but seems filterOptions() runs for every key inputs.

It would be great if react-select has some way to cancel filtering, e.g. preventDefault() or shouldComponentUpdate() in onInputChange(). Because it enables us to debounce filtering.

[jayaramkasi]

#3254 This is a related PR

[lukebennett88]

Hi @Quazie,

In an effort to sustain the react-select project going forward, we're cleaning up old issues and pull requests.

As this suggestion would be a breaking change, I've added the 6.0 milestone to this issue, and will move it to the ideas section discussions