code: public static byte[] readBytes(InputStream is) throws IOException {
          if (is == null) {
              return null;
          }
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          copyStream(is, baos);
          return baos.toByteArray();
      }
docs: Read an <code>InputStream</code> into <code>byte[]</code> until EOF.
  <br>
  Does not close the InputStream!
  
  @param is the stream to read the bytes from
  @return all read bytes as an array
  @throws IOException when read or write operation fails