Start Updating selfpopulatingcache example

Updating selfpopulatingcache example

After some time passes, the loader will be called again.

Even minor version, stable release, new features and compatible changes to the previous version.

Not be strictly binary compatible to the previous stable release.

If we never did fly on that route it will ask all our friends.

Of course this is very time consuming, so we first ask the cache, whether something for that flight route is already known, if not, we call the expensive operation.

A typical example is the optimization of HTTP requests.

When the current cached value and its time is known the request header will block until the loading is completed and return the new value.

In this case mutating cached values directly will lead to inconsistent results.