public enum ReactiveCocoaEventType {
    case Started
    case Next
    case Completed
    case Failed
    case Terminated
    case Disposed
    case Interrupted

    public static let allEvents: Set<ReactiveCocoaEventType> = {
        return [.Started, .Next, .Completed, .Failed, .Terminated, .Disposed, .Interrupted]
    }()
}

extension SignalProducerType {
    @warn_unused_result(message="Did you forget to call `start` on the producer?")
    public func logEvents(events: Set<ReactiveCocoaEventType> = ReactiveCocoaEventType.allEvents, withMessage message: String, onLogger logger: XCGLogger = log, logLevel: XCGLogger.LogLevel = .Debug, fileName: String = #file, functionName: String = #function, lineNumber: Int = #line) -> SignalProducer<Self.Value, Self.Error> {
        let logEvent = { (text: String) in
            logger.logln("[\(message)] \(text)", logLevel: logLevel, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
        }

        typealias OptionalClosure = (() -> ())?

        let started: OptionalClosure = events.contains(.Started) ? {
            logEvent("Started")
        } : nil

        let failed: ((Self.Error) -> ())? = events.contains(.Failed) ? { error in
            logEvent("Failed with error: \(error)")
        } : nil

        let next: ((Self.Value) -> ())? = events.contains(.Next) ? { value in
            logEvent("Next: \(value)")
        } : nil

        let completed: OptionalClosure = events.contains(.Completed) ? {
            logEvent("Completed")
        } : nil

        let interrupted: OptionalClosure = events.contains(.Interrupted) ? {
            logEvent("Interrupted")
        } : nil

        let terminated: OptionalClosure = events.contains(.Terminated) ? {
            logEvent("Terminated")
        } : nil

        let disposed: OptionalClosure = events.contains(.Disposed) ? {
            logEvent("Disposed")
        } : nil

        return self.on(started: started, failed: failed, completed: completed, interrupted: interrupted, terminated: terminated, disposed: disposed, next: next)
    }
}