background update feature

[klh]

When using throttle &/or cache it would be beneficial to have a
fast return Cache, but update (if possible) Cache in background as a post event.

so instead of (pseudo code):

.get('my/url')
->respond with getFromCache('my/url')

do this:

.get('my/url')
->respond with getFromCache('my/url')
send('my/url')
->updateCache with result from my/url request

[kuitos]

It prefer to provide the upper ability in your own application but not the underlying library.
duplicated with #52

[klh]

sure that's a duplicate?'
The intention was to always respond fast, and take the hit on a long loading endpoint in the background - and next request would then have an updated cache item?

so 1 get would be equivalent to:

get->returnFromCache->get->request->updatedCache

[kuitos]

Sorry for my mistake.
U could wrap your request method, and makes them do a background forceUpdate after every call.
eg.

async function request() {
  const res  = await http.get('/url');
  http.get('/url', { forceUpdate: true })
  return res
}