code: public static long copy(InputStream is, OutputStream os) throws IOException {
      return new StreamCopier(is, os).copy();
    }
docs: Copies an {@link InputStream} to and {@link OutputStream} using {@link Channels}.
  
  <p>
  <b>Note:</b> The method does not close the {@link InputStream} and {@link OutputStream}. However, the
  {@link ReadableByteChannel} and {@link WritableByteChannel}s are closed
  </p>
  
  @return Total bytes copied