code: private CodeBlock.Builder initMethodCallCode( MapperInstance instance ) {
          CodeBlock.Builder builder = CodeBlock.builder();
          if ( null == instance.getInstanceCreationMethod().isConstructor() ) {
              builder.add( "$T.$L", rawName( instance.getMapperType() ), instance.getInstanceCreationMethod().getName() );
          } else {
              builder.add( "new $T", typeName( instance.getMapperType() ) );
          }
          return builder;
      }
docs: Initialize the code builder to create a mapper.
  
  @param instance the class to call
  
  @return the code builder to create the mapper