namespace System.Collections.Immutable
{
    [DebuggerDisplay("Count = {Count}")]
    [DebuggerTypeProxy(typeof(ImmutableDictionaryDebuggerProxy<?, ?>))]
    [DefaultMember("Item")]
    public sealed class ImmutableSortedDictionary<TKey, TValue> : ICollection<KeyValuePair<TKey, TValue>>, IDictionary<TKey, TValue>, IEnumerable<KeyValuePair<TKey, TValue>>, IReadOnlyCollection<KeyValuePair<TKey, TValue>>, IReadOnlyDictionary<TKey, TValue>, ICollection, IDictionary, IEnumerable, IImmutableDictionary<TKey, TValue>
        where TKey, notnull
    {
        public IEnumerable<TKey>! Keys { get; }
    }
}