Error try to download 3gpp from server using retrofit?

Question

Hi i try to download 3gpp file from server

@GET("/{filename}")
@Streaming
public void getFileFromServer(
        @Path("filename") String filename,
        Callback<Response> callback
);

and my calling code is

RestAdapter restAdapter = new RestAdapter.Builder()
        .setEndpoint("http://xxx.xxx.xx.xx/api/")  //call your base url
        .build();
MyApi myapi = restAdapter.create(MyApi.class);
 myApi.getFileFromServer(Filename, new Callback<Response>() {
        @Override
        public void success(Response response, Response response1) {
            Log.w("CMS Return", "");
            File direct = new File(Environment.getExternalStorageDirectory() + Constants.LocalImageSaveLastStringDirectory + Constants.LocalVoiceSaveLastStringDirectory);

            if (!direct.exists()) {
                File wallpaperDirectory = new File(Constants.LocalvoiceSaveFullDirectory);
                wallpaperDirectory.mkdirs();
            }

            String fileName1 = getLastWord(Filename);

            File pdfFile = new File(new File(Constants.LocalvoiceSaveFullDirectory), fileName1);
            if (pdfFile.exists()) {
                pdfFile.delete();
            }

            FileOutputStream output = null;
            try {
                output = new FileOutputStream(pdfFile);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
            try {
                TypedInput body = response.getBody();

                String bodyMime = body.mimeType();
                byte[] bodyBytes = streamToBytes(body.in());

                org.apache.commons.io.IOUtils.write(bodyBytes, output);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void failure(RetrofitError error) {
            System.out.println("Check retrofit Value" + error);

        }
    });

Stream to bytes method

   private static byte[] streamToBytes(InputStream stream) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    if (stream != null) {
        byte[] buf = new byte[BUFFER_SIZE];
        int r;
        while ((r = stream.read(buf)) != -1) {
            baos.write(buf, 0, r);
        }
    }
    return baos.toByteArray();
}

And i got crash on stream.read(buf)) i debug this issue network main thread issue how to solve or how to download 3gp voice file from server