Example of new Swift 3 swiftier GCD syntax

ToSwift3.swift

// Swift 2.x

public class func GCDDelay(delayAmount:Float, block:(Void->Void)) {
    dispatch_after(dispatch_time(dispatch_time_t(DISPATCH_TIME_NOW), 
        Int64(delayAmount * Float(NSEC_PER_SEC))), dispatch_get_main_queue(), block)
}

GCDDelay(0.5) { UIApplication.sharedApplication.openURL(url) }

// Swift 3

public class func GCDDelay(_ delayAmount:Double, block:((Void)->Void)) {
    DispatchQueue.main.after(when: .now() + delayAmount, execute: block)
}

// or just this
DispatchQueue.main.after(when: .now() + 0.5) { UIApplication.sharedApplication.openURL(url) }