<PackageReference Include="System.Collections.Immutable" Version="11.0.0-rc.1.26425.128" />

System.Collections.Immutable.IImmutableQueue<T>

public interface IImmutableQueue<T> : IEnumerable<T>, IEnumerable
Represents an immutable first-in, first-out collection of objects. NuGet package: System.Collections.Immutable (about immutable collections and how to install)
namespace System.Collections.Immutable { public interface IImmutableQueue<[Nullable(2)] T> : IEnumerable<T>, IEnumerable { bool IsEmpty { get; } IImmutableQueue<T> Clear(); T Peek(); IImmutableQueue<T> Enqueue(T value); IImmutableQueue<T> Dequeue(); } }