System.Runtime by Microsoft

<PackageReference Include="System.Runtime" Version="4.0.21-beta-23409" />

 Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult>

public sealed delegate Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TResult> : MulticastDelegate
Encapsulates a method that has nine parameters and returns a value of the type specified by the TResult parameter.
public Func(object object, IntPtr method)

public virtual IAsyncResult BeginInvoke(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8, T9 arg9, AsyncCallback callback, object object)

public virtual TResult EndInvoke(IAsyncResult result)

public virtual TResult Invoke(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8, T9 arg9)