Nuke 6.0-beta1

About 8 months ago I started using Nuke in production. The project has matured from being a playground for experimenting with Swift features to something that I rely on in my day job. The primary goal behind Nuke 6 is to simplify the project even further and to get rid of the implementation details leaking into a public API.

Nuke is now Swift 4 only. It's simpler, smaller (< 1000 lines of code), and faster. It features progress reporting and makes it simpler to create custom data loader (e.g. Alamofire data loader).

Features

• Implements progress reporting #81

Removed APIs

• Remove global loadImage(...) functions #142
• Remove Deduplicator class, make this functionality part of Loader. This has a number of benefits: reduced API surface, improves performance by reducing number of queue switching, enables new features like progress reporting.
• Remove schedulers (DispatchQueueScheduler, OperationQueueScheduler, etc). This whole infrastructure was way too excessive.
• Make RateLimiter private.

Improvements

• Replace Foundation.OperationQueue & custom Foundation.Operation subclass with a new TaskQueue type. It's simpler, faster, and gets rid of pesky Thread Sanitizer warnings #141
• DataLoader now works with URLRequest, not Request
• Loader now always calls completion on the main thread.
• Move URLResponse validation from DataDecoder to DataLoader
• Make use of some Swift 4 feature like nested types inside generic types.