anchor.diff:  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
   
  
positive.code:     }
      
      @Override
      public Object convert(
              AbstractNode node, String transform, Map<Object, Object> o) {    // <2>
  
          if (transform == null) {                                             // <3>
  
negative.code:  
          if (node instanceof DocumentRuby) {
              DocumentRuby document = (DocumentRuby) node;
              return document.getContent().toString();                         // <4>
          } else if (node instanceof Section) {
              Section section = (Section) node;
              return new StringBuilder()
  