"Declaring Unmanaged Function Pointers"

delegate* unmanaged<int, int> automaticConventionFuncPtr;
delegate* unmanaged[Cdecl]<int, int> cdeclConventionFuncPtr;
delegate* unmanaged[Fastcall]<int, int> fastcallConventionFuncPtr;
delegate* unmanaged[Stdcall]<int, int> stdcallConventionFuncPtr;
delegate* unmanaged[Thiscall]<int, int> thiscallConventionFuncPtr;


Code snippet taken from "Two Decades of C#: A Reference - C# 9".