}

    /**
     * Creates a {@link CaseInsensitiveSet}.
     *
     * @param c the collection to copy from
     */
    public CaseInsensitiveSet(final Collection<String> c) {
        map = new CaseInsensitiveMap<>(Math.max((int) (c.size() / .75f) + 1, 16));
        addAll(c);
    }

    /**
     * Creates a {@link CaseInsensitiveSet}.
     *
     * @param initialCapacity the initial capacity
     */

import java.util.SequencedCollection;

// Enhanced collection creation
List<String> list = CollectionsUtil.newArrayList();
Map<String, Object> map = CollectionsUtil.newLinkedHashMap();
Set<String> caseInsensitiveSet = new CaseInsensitiveSet<>();

// Java 21 Sequenced Collections support
SequencedCollection<String> sequenced = CollectionsUtil.newLinkedHashSet();
String first = CollectionsUtil.getFirst(sequenced);