code: public InputStream getInputStream() {
          if (this.data instanceof InputStream) {
              return (InputStream) this.data;
          } else {
              final Reader reader = (Reader) this.data;
              return new ReaderInputStream(reader, getCharset());
          }
      }
docs: Returns an {@code InputStream} over the binary data of this representation object.
  Conversion from character to byte data, if required, is performed according to the charset
  specified by the MIME type metadata property ({@link NIE#MIME_TYPE}).
  
  @return an {@code InputStream} over the binary content of this representation