"Tuple Type Declaration"

static readonly List<(int Age, string Name, float TestScore)> _userList;

static void AddUserToList((int Age, string Name, float TestScore) user) {
	_userList.Add(user);
}

// ...

static void Test() {
	AddUserToList((30, "Ben", 50f));
}


Code snippet taken from "Two Decades of C#: A Reference - C# 7".