C#

FileStream fs = new FileStream("X:\\file.dat", FileMode.Open, FileAccess.Read);

                                    // Create a byte array of file stream length
                                    byte[] writeArray = new byte[fs.Length];

                                    //Read block of bytes from stream into the byte array
                                    fs.Read(writeArray, 0, System.Convert.ToInt32(fs.Length));

                                    //Close the File Stream
                                    fs.Close();

                                    // Create a synchronization object that gets 
                                    // signaled when verification is complete.
                                    ManualResetEvent manualEvent = new ManualResetEvent(false);

                                    FileStream fStream = new FileStream("X:\\archive\file.dat", FileMode.Create, FileAccess.ReadWrite, FileShare.None, 4096, true);

                                    // Check that the FileStream was opened asynchronously.
                                    Debug.Print("fStream was {0}opened asynchronously.", fStream.IsAsync ? "" : "not ");

                                    // Asynchronously write to the file.
                                    IAsyncResult asyncResult = fStream.BeginWrite
                                        (
                                        writeArray,
                                        0,
                                        writeArray.Length,
                                        new AsyncCallback(EndWriteCallback),
                                        new State(fStream, writeArray, manualEvent)
                                        );

fs.Read(writeArray, 0, System.Convert.ToInt32(fs.Length));