docs: @GwtIncompatible("OutputStream")
    static OutputStream asOutputStream(final ByteOutput output) {
      checkNotNull(output);
      return new OutputStream() {
        @Override
        public void write(int b) throws IOException {
          output.write((byte) b);
        }
  
        @Override
        public void flush() throws IOException {
          output.flush();
        }
  
        @Override
        public void close() throws IOException {
          output.close();
        }
      };
    }