<PackageReference Include="NETStandard.Library" Version="2.0.0" />

System.MarshalByRefObject

public abstract class MarshalByRefObject
namespace System { public abstract class MarshalByRefObject { protected MarshalByRefObject(); public object GetLifetimeService(); public virtual object InitializeLifetimeService(); protected MarshalByRefObject MemberwiseClone(bool cloneIdentity); } }