 
      - parameter data: The data to send to the Speech to Text service.
      */
-    override func writeData(data: NSData) {
+    override func writeData(data: NSData, completion: (Void -> Void)? = nil) {
         operations.addOperationWithBlock {
             if self.state == .Listening {
                 self.state = .StartedRequest


     - parameter str: The string to send to the Speech to Text service.
     */
    override func writeString(str: String) {
        operations.addOperationWithBlock {
            if self.state == .Listening {
                self.state = .StartedRequest


     - parameter data: Data to include in the ping to the Speech to Text service.
     */
    override func writePing(data: NSData, completion: (Void -> Void)? = nil) {
        operations.addOperationWithBlock {
            super.writePing(data)
        }
