<PackageReference Include="System.Reactive" Version="6.0.2" />

ReadyToken

static class ReadyToken
Holds onto a singleton IDisposable indicating a ready state.
using System.Runtime.CompilerServices; namespace System.Reactive { internal static class ReadyToken { private sealed class ReadyDisposable : IDisposable { public void Dispose() { } } [System.Runtime.CompilerServices.Nullable(1)] internal static readonly IDisposable Ready = new ReadyDisposable(); } }