code: private void writeInt(OutputStream out, int i) throws IOException {
          out.write((byte) (i >> 24));
          out.write((byte) (i >> 16));
          out.write((byte) (i >> 8));
          out.write(i);
      }
docs: OutputStream.write(int) 仅 write 第一个 byte, 而不是整个 int
  
  @param out OutputStream
  @param i int value
  @throws IOException if an I/O error occurs.