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

System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TResult>

public sealed delegate Func<T1, T2, T3, T4, T5, T6, T7, T8, TResult> : MulticastDelegate
namespace System { public delegate TResult Func<in T, out TResult> (T arg); }