<PackageReference Include="NUnit" Version="4.4.0" />

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 { [System.Runtime.CompilerServices.NullableContext(1)] public interface IEvent<[System.Runtime.CompilerServices.Nullable(2)] in TListener> { void Send(TListener listener); } }