try {
            final FileChannel channel = in.getChannel();
            final ByteBuffer buffer = ByteBuffer.allocate(DEFAULT_BUF_SIZE);
            final byte[] buf = buffer.array();
            int len;
            int amount = 0;
            while ((len = ChannelUtil.read(channel, buffer, amount)) != -1) {
                out.write(buf, 0, len);
                buffer.clear();