Add prepend and append strategy

[Nyholm]

Im currently working on HTTPlug bundle and I will soon be in need for prepending a strategy to the existing ones. That is why I need a getter.

[sagikazarmark]

Why do you need a getter? Wondering about valid usecases, because strategies are internal thing, we shouldn't rely on them.

[Nyholm]

I have an idea (work in progress). The HTTPlug's web toolbar shows all requests made by registered clients. But if a third party library uses discovery to find a client, that request will not be logged in the toolbar.

My plan in to prepend the current list of strategies with a custom one made for HTTPlug. It would be a strategy of registered clients. I think I can make that work... Anyhow I need to do something like this:

$currentStrategies = HttpClientDiscovery::getStrategies();
$strategies = array_unshift($currentStrategies, CustomStrategy::class);
HttpClientDiscovery::setStrategies(strategies);

[sagikazarmark]

For that, I would rather suggest something like prependStrategy method. (You can also add appendStrategy)

[sagikazarmark]

Would you prefer to merge and release 0.9.x or you wait for 1.0 in the HttplugBundle PR?

[Nyholm]

Let's wait a couple of days.. Ill reference this PR in a larger one in HttplugBundle

[sagikazarmark]

Okay, let's wait with the tag, but is this ready? Can it be merged?

[Nyholm]

Yes. I believe so.