<PackageReference Include="NUnit" Version="4.3.0" />

IEvent<TListener>

public interface IEvent<TListener>
Interface for ALL event types that can be queued for processing.
using System.Runtime.CompilerServices; namespace NUnit.Framework.Internal.Execution { [NullableContext(1)] public interface IEvent<[Nullable(2)] in TListener> { void Send(TListener listener); } }