How can I cancel Google Drive Uploads?

Question

I'm testing Google Drive API with this code :

public void UploadVideo() {
    Drive.DriveApi.newDriveContents(gac).setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
        public void onResult(final DriveApi.DriveContentsResult result) {
            new Thread() {
                public void run() {
                    BufferedInputStream bis = null;
                    BufferedOutputStream bos = null;
                    try {
                        bis = new BufferedInputStream(new FileInputStream("/sdcard/my_video.avi"));
                        bos = new BufferedOutputStream(result.getDriveContents().getOutputStream());

                        final int BUFFER_SIZE = 8192;
                        byte buffer[] = new byte[BUFFER_SIZE];
                        int n;

                        while ((n = bis.read(buffer, 0, BUFFER_SIZE)) != -1)
                            bos.write(buffer, 0, n);

                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    finally {
                        if(bis != null) {
                            try {
                                bis.close();
                            } catch (IOException e) {
                            }
                        }
                        if(bos != null) {
                            try {
                                bos.close();
                            } catch (IOException e) {
                            }
                        }
                    }

                    MetadataChangeSet mcs = new MetadataChangeSet.Builder()
                            .setMimeType("video/x-msvideo")
                            .build();

                    IntentSender is = Drive.DriveApi.newCreateFileActivityBuilder()
                            .setActivityTitle("File name to save")
                            .setInitialMetadata(mcs)
                            .setInitialDriveContents(result.getDriveContents())
                            .build(gac);

                    try {
                        startIntentSenderForResult(is, 54321, null, 0,0,0);
                    } catch (IntentSender.SendIntentException e) {
                        e.printStackTrace();
                    }
                }
            }.start();
        }
    });
}

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (54321 == requestCode) {
        if(resultCode == RESULT_OK) {
            DriveId writtenFileID = data.getParcelableExtra(OpenFileActivityBuilder.EXTRA_RESPONSE_DRIVE_ID);
            DriveFile writtenFile = writtenFileID.asDriveFile();
            writtenFile.getMetadata(gac)
                    .setResultCallback(new ResultCallback<DriveResource.MetadataResult>() {
                        public void onResult(DriveResource.MetadataResult metadataResult) {
                            Metadata md = metadataResult.getMetadata();
                            String s = md.getTitle() + "\n"
                                    + md.getMimeType() + "\n"
                                    + md.getFileSize();
                            Toast.makeText(getApplicationContext(), s, Toast.LENGTH_LONG).show();
                        }
                    });
        }
    }
}

The problem is, this works asynchronously EVEN WHEN I CLOSE THE APP, so there's no way to stop the upload. I'm testing with a file sized around 250MB, but all my code above runs IMMEDIATELY TO THE END, including the onActivityResult() callback method. My internet is very slow and I can see the complete uploaded file from my GDrive about in five minutes or so.

Is there any way to stop uploading or synchronous method for uploading?