Replace RequestContext initialization parameters with associatedtype

[adam-fowler]

Instead of

struct MyRequestContext: RequestContext {
    var coreContext: CoreRequestContext
    init(channel: Channel, logger: Logger) {
        self.coreContext = .init(allocator: channel.allocator, logger: logger)
    }
}

You have where, Source is the source of the request

struct MyRequestContext: RequestContext {
    var coreContext: CoreRequestContext
    init(source: Source) {
        self.coreContext = .init(source: Source)
    }
}

In the server situation Source is a struct that includes the logger and the channel. You can still access the channel via source.channel. In the lambda situation this would include the Event that triggered the lambda and the LambdaContext.

It makes context creation simpler and hides implementation details

[Joannis]

I like this a lot. My only "concern" is that we lose the ability to add more properties to CoreRequestContext later with this setup. With the old setup, we could've added secondary inits to CoreRequestContext. Not sure if that's a fair concern though

[adam-fowler]

I like this a lot. My only "concern" is that we lose the ability to add more properties to CoreRequestContext later with this setup. With the old setup, we could've added secondary inits to CoreRequestContext. Not sure if that's a fair concern though

Not sure how this affects your ability to write a secondary init for CoreRequestContext. You can still do that and call it from your custom context.

EDIT: @Joannis I think I get what you're at. If we require additional parameters from Channel we would have to extend the requirements for RequestContextSource. Yeah I don't think that this is an issue. If we needed other values from the Channel in the Hummingbird Library we would have found them now