private byte[] _sendPostRequest(@Nonnull final String url, @Nonnull final byte[] requestData)
            throws URISyntaxException, CopyException {
        HttpRequest.Builder requestBuilder = createMusicImportRequest(new URI(url), requestData);
        return makeMusicServiceRequest(requestBuilder);
    }
@return the total number of playlist tracks acknowledged by the Apple Music Library Service in this page
extensions/data-transfer/portability-data-transfer-apple/src/main/java/org/datatransferproject/datatransfer/apple/music/AppleMusicInterface.java