anchor.diff:      }
       
       @Override
  -    public Object convert(
  +    public String convert(
               AbstractNode node, String transform, Map<Object, Object> o) {    // <2>
   
           if (transform == null) {                                             // <3>
  
positive.code:  
          if (node instanceof DocumentRuby) {
              DocumentRuby document = (DocumentRuby) node;
              return document.getContent();                                    // <4>
          } else if (node instanceof Section) {
              Section section = (Section) node;
              return new StringBuilder()
  
negative.code: File adocFile = ...
  asciidoctor.convertFile(adocFile, OptionsBuilder.options().backend("text"));
  ----
  
  It is also possible to provide converters for binary formats.
  In this case the converter should extend the generic class `org.asciidoctor.converter.AbstractConverter<T>` where `T` is the return type of the method `convert()`.
  `StringConverter` is actually a concrete subclass for the type `String`.
  
  == Loading Ruby libraries
  
  