code: public static boolean shouldReturnThis(JavacNode field) {
  		if ((((JCVariableDecl) field.get()).mods.flags & Flags.STATIC) != 0) return false;
  		
  		AnnotationValues<Accessors> accessors = JavacHandlerUtil.getAccessorsForField(field);
  		
  		return HandlerUtil.shouldReturnThis0(accessors, field.getAst());
  	}
docs: When generating a setter, the setter either returns void (beanspec) or Self (fluent).
  This method scans for the {@code Accessors} annotation to figure that out.