     
     private mutating func dequeueElementOnly() -> T {
         precondition(count > 0)
-        
-        version++
         
         let index = dequeueIndex
         let value = storage[index]!

        var i = dequeueIndex
        var count = _count
        
        let lastVersion = version
        
        return anyGenerator {
            if lastVersion != self.version {
                rxFatalError("Collection was modified while enumerated")
            }
            
            if count == 0 {
                return nil
            }

    - parameter element: Element to enqueue.
    */
    public mutating func enqueue(element: T) {
        if count == storage.count {
            resizeTo(max(storage.count, 1) * resizeFactor)
        }
