We need to add some documentation about the status header that is set after each request.

If we want to follow the HTTP specification we need to add/remove warning headers at the right moment as seen here: https://tools.ietf.org/html/rfc7234#section-5.5

Problem: If HttpResponseMessage.Content is read with ReadAsAsync the stream will be consumed. This causes issues when the user then tries to read the content of a cached response resulting in a null stream.

Solution: Serialise the response before adding it to the cache and deserialise it before retrieving it. This should be done with HttpContent.

We explicitly create an empty instance of HttpClientHandler in our constructor, this makes the API cleaner and easier to use but it's totally unnecessary if the user wants to create its own and use some of its functionality.

Current constructor:

public HttpCachingHandler(IHttpCache cache, ICacheKeyStrategy keyStrategy)
{
    _cache = cache ?? throw new ArgumentNullException(nameof(cache));
    _keyStrategy = keyStrategy ?? throw new ArgumentNullException(nameof(keyStrategy));
    InnerHandler = new HttpClientHandler(); //This should be moved to its own parameter
}

Seems like I forgot to add ConfigureAwait(false) to all async calls, we need to add them just to be sure.

The following code can probably be simplified to make it more readable, it's important to have keys in the same format!

 //todo: Simplify this
var varyHeaders = request.Headers.Where(x => response.Headers.Vary.Any(y => y.Equals(x.Key, StringComparison.CurrentCultureIgnoreCase))).SelectMany(o => o.Value);
var formattedVaryheaderString = varyHeaders.Aggregate("", (current, varyHeader) => current + (VaryHeaderDelimiter + varyHeader));

As the title states, what should we do when the CacheControl header on the request is null? At the moment we assign an empty header if it's null which does not seem entirely correct.

Commit that added functionality: 2467a35

The code in the HandleServerResponse method is a bit hard too follow, we should probably try to clean it up and make it easier to follow.

We need to fix the logo since its edges are a bit pixelated in the larger formats.