v6.0.0 - async/await

1. Support async/await with new Promise.value()

v5.1.0 - Combine

1. Support Combine framework with new .publisher() method

v5.0.0 - Swift 5.0

1. Built with Swift 5.0

v4.0.0 - Swift 4.2

1. Built for Swift 4.2

v3.0.0 - Unfair Lock

1. On iOS 10+ and macOS 10.12+ the locking mechanism for Promise is backed by os_unfair_lock bringing a significant performance improvement. On prior versions of iOS and macOS the locking mechanism falls back to a serial DispatchQueue
2. Expose a new Lock class that hides the implementation detail of the underlying lock, preferring os_unfair_lock when available, and falling back to a serial DispatchQueue when it's not.

v2.4.0 - Promise Cancellation

1. Add Promise.cancel
2. Add Promise { resolve, reject, onCancel in }

v2.2.0 - tapCatch

1. Add Promise.tapCatch

v2.1.0 - Docs, SPM, Return

1. Add Promise.return
2. Support CocoaPods v1.4.0
3. Support Swift Package Manager
4. Hosted documentation generated with Jazzy

v2.0.1 - Swift Package Manager

1. Add missing Foundation imports for Swift Package Manager

v2.0.0 - Swift 4

1. Swift 4 and Xcode 9
2. Renamed catchThen to recover
3. Added Promise/A+ test suite