namespace System.Collections.Immutable { public static class ImmutableList { public static ImmutableList<T> Create<T>(); public static ImmutableList<T> Create<T>(T item); public static ImmutableList<T> CreateRange<T>(IEnumerable<T> items); public static ImmutableList<T> Create<T>(params T[] items); public static ImmutableList<T>.Builder CreateBuilder<T>(); public static ImmutableList<TSource> ToImmutableList<TSource>(this IEnumerable<TSource> source); public static IImmutableList<T> Replace<T>(this IImmutableList<T> list, T oldValue, T newValue); public static IImmutableList<T> Remove<T>(this IImmutableList<T> list, T value); public static IImmutableList<T> RemoveRange<T>(this IImmutableList<T> list, IEnumerable<T> items); public static int IndexOf<T>(this IImmutableList<T> list, T item); public static int IndexOf<T>(this IImmutableList<T> list, T item, IEqualityComparer<T> equalityComparer); public static int IndexOf<T>(this IImmutableList<T> list, T item, int startIndex); public static int IndexOf<T>(this IImmutableList<T> list, T item, int startIndex, int count); public static int LastIndexOf<T>(this IImmutableList<T> list, T item); public static int LastIndexOf<T>(this IImmutableList<T> list, T item, IEqualityComparer<T> equalityComparer); public static int LastIndexOf<T>(this IImmutableList<T> list, T item, int startIndex); public static int LastIndexOf<T>(this IImmutableList<T> list, T item, int startIndex, int count); } }