docs: public static <T> String join(String delimiter, Collection<T> strings) {
          StringBuilder builder = new StringBuilder();
          boolean first = true;
          for (T o : strings) {
              if (first) {
                  first = false;
              } else {
                  builder.append(delimiter);
              }
              builder.append(Objects.toString(o));
          }
          return builder.toString();
      }