A swift singleton initialiser that also allows for configuration of the singleton when it is first created.

SwiftSingleton

class var sharedInstance {
    struct Static {
        static let instance : SingletonObject = SingletonObject()
        static var onceToken : dispatch_once_t = 0
    }
    dispatch_once(&Static.onceToken) {
        //perform configuration here
    }
    return Static.instance
}