DeconstructionBenchmark.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using BenchmarkDotNet.Engines;

[MemoryDiagnoser]
public class DictionaryIterationBenchmark
{
    private Dictionary<string, int> dict = null!;

    [Params(10, 1_000, 100_000)]
    public int Size;

    private readonly Consumer consumer = new Consumer();

    [GlobalSetup]
    public void Setup()
    {
        dict = new Dictionary<string, int>(Size);
        for (int i = 0; i < Size; i++)
        {
            dict[$"Key{i}"] = i;
        }
    }

    [Benchmark(Baseline = true)]
    public void IterateWithKeyValuePair()
    {
        foreach (var kvp in dict)
        {
            // Do some real work so JIT can’t optimize away
            consumer.Consume($"{kvp.Key}:{kvp.Value}");
        }
    }

    [Benchmark]
    public void IterateWithDeconstruction()
    {
        foreach (var (fruit, count) in dict)
        {
            consumer.Consume($"{fruit}:{count}");
        }
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        BenchmarkRunner.Run<DictionaryIterationBenchmark>();
    }
}