code: public static CodeBlock join(Iterable<CodeBlock> codeBlocks, String separator) {
      return StreamSupport.stream(codeBlocks.spliterator(), false).collect(joining(separator));
    }
docs: Joins {@code codeBlocks} into a single {@link CodeBlock}, each separated by {@code separator}.
  For example, joining {@code String s}, {@code Object o} and {@code int i} using {@code ", "}
  would produce {@code String s, Object o, int i}.