String filename = exchange.getRequest().getRequestURI();
RandomAccessFile raf = new RandomAccessFile(filename, "r");
HttpResponseHeader header = new HttpResponseHeader(200);
header.addHeader("x-length", Long.toString(raf.length()));
BodyDataSink outChannel = exchange.send(header, (int) raf.length());
AsyncWriter asyncWriter = new AsyncWriter(outChannel, raf);
asyncWriter.onWritten(0);
}