System.Collections.Frozen.FrozenSet public static class FrozenSet Provides a set of initialization methods for instances of the FrozenSet<T> class. Documentation Code namespace System.Collections.Frozen { public static class FrozenSet { public static FrozenSet<T> Create<[System.Runtime.CompilerServices.Nullable(2)] T>(ReadOnlySpan<T> source); public static FrozenSet<T> Create<[System.Runtime.CompilerServices.Nullable(2)] T>(IEqualityComparer<T> equalityComparer, ReadOnlySpan<T> source); public static FrozenSet<T> ToFrozenSet<[System.Runtime.CompilerServices.Nullable(2)] T>(this IEnumerable<T> source, IEqualityComparer<T> comparer = null); } }