code: @NotNull
      public static Collector<CharSequence, ?, String> joining(
              @NotNull CharSequence delimiter,
              @NotNull CharSequence prefix,
              @NotNull CharSequence suffix) {
          return joining(delimiter, prefix, suffix, prefix.toString() + suffix.toString());
      }
docs: Returns a {@code Collector} that concatenates input elements into new string.
  
  @param delimiter  the delimiter between each element
  @param prefix  the prefix of result
  @param suffix  the suffix of result
  @return a {@code Collector}