docs: public TextWriterWriterInterface<?> getWriterFor(Object o) {
      if(o == null) {
        return null;
      }
      TextWriterWriterInterface<?> writer = writers.getHandler(o);
      if(writer != null) {
        return writer;
      }
      try {
        final Class<?> decl = o.getClass().getMethod("toString").getDeclaringClass();
        if(decl == Object.class) {
          return null; // TODO: cache this, too
        }
        writers.insertHandler(decl, fallbackwriter);
        return fallbackwriter;
      }
      catch(NoSuchMethodException | SecurityException e) {
        return null;
      }
    }