le)) {
    if (leftDelimiter == &quot;(&quot; &amp;&amp; rightDelimiter == &quot;)&quot;) {
      &#47;&#47; Avoid creating a new string in the &quot;common&quot; case.
      return &quot;(...)&quot;;
    }
    return &quot;$leftDelimiter...$rightDelimiter&quot;;
  }
  List&lt;String&gt; parts = &lt;String&gt;[];
  _toStringVisiting.add(iterable);
  try {
    _iterablePartsToStrings(iterable, parts);
  } finally {
    assert(identical(_toStringVisiting.last, iterable));
    _toStringVisiting.removeLast();
 