 private extension NSData {
     
     private func wrapToDispatchData(copy copy: Bool) -> dispatch_data_t {
-        var ret: dispatch_data_t?
+        var ret = dispatch_data_empty
         enumerateByteRangesUsingBlock { (bytes, byteRange, _) in
             let chunk: dispatch_data_t
             if copy {


extension Data {
    
    public init(_ data: NSData) throws {
        try self.init(data.dispatchValue)
    }
    
}

                    innerData.release()
                }
            }
            ret = dispatch_data_create_concat(ret, chunk)
        }
        return ret
    }
    
    @nonobjc var dispatchValue: dispatch_data_t {
