How to check from within a Rust function if it is called directly or by Invoke() from C# code?

I am calling a Rust function in a native DLL from C# like this:

[DLLImport("rust.dll")]
public static int Foo(int i);
public static void Invoke() {
    typeof(Program).GetMethod("Foo").Invoke(new object[] {null}, new object[] {1});
}
public static void Call() {
    Foo(1);
}

I want to check if a the method is called directly or by using Invoke. If it's invoked the method should print "Invoked", if not it should print "Called". I'm not really sure if you can differentiate between these two things, thats why I'm asking :P.