// PROJECT-EXAMPLE
void Add(scoped ref int value) { value += 2; }
int count = 3;
Add(ref count);
System.Console.WriteLine(count);

static int Sum(scoped ReadOnlySpan<int> values);
static void Add(scoped ref int value, int amount);

using System;

internal static class Program
{
    public static void Main()
    {
        ReadOnlySpan<int> readings = stackalloc int[] { 3, 5, 7 };
        Console.WriteLine(Sum(readings));
    }
    private static int Sum(scoped ReadOnlySpan<int> values)
    {
        int total = 0;
        foreach (int value in values) total += value;
        return total;
    }
}

using System;

internal static class Program
{
    public static void Main()
    {
        int points = 10;
        Add(ref points, 4);
        Add(ref points, 6);
        Console.WriteLine(points);
    }
    private static void Add(scoped ref int value, int amount)
    {
        value += amount;
    }
}