code: @CanIgnoreReturnValue
    public final <A extends Appendable> A appendTo(
        A appendable, @NullableDecl Object first, @NullableDecl Object second, Object... rest)
        throws IOException {
      return appendTo(appendable, iterable(first, second, rest));
    }
docs: Appends to {@code appendable} the string representation of each of the remaining arguments.