@Override
                protected int colIndexOfKey(Object key) {
                    return indexOf(key);
                }
{@inheritDoc}

<p>This implementation composes a string by iterating over its values. If
this set contains itself as a value, the string "(this Set)"
will appear in its place.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/collection/ArraySet.java