== Resources

=== Documentation

* https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/sealed[The `sealed` keyword]

=== Articles & blog posts

* https://code-maze.com/improve-performance-sealed-classes-dotnet[Boosting Performance With Sealed Classes in .NET]
* https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-6/#peanut-butter[Performance Improvements in .NET 6]

=== Benchmarks

[options="header"]
|===
|Method         | Runtime  | Mean       | StdDev | Ratio
| UnsealedType  | .NET 5.0 |   918.7 us   | 10.72 us |  1.00 
| SealedType    | .NET 5.0 | 231.2 us     |  3.20 us |  0.25 
| UnsealedType  | .NET 6.0 | 867.9 us     |  5.65 us |  1.00 
| SealedType    | .NET 6.0 | 218.4 us     |  0.59 us |  0.25 
| UnsealedType  | .NET 7.0 | 1,074.5 us   |  3.15 us |  1.00 
| SealedType    | .NET 7.0 | 216.1 us     |  1.19 us |  0.20 
|===

The results were generated by running the following snippet with https://github.com/dotnet/BenchmarkDotNet[BenchmarkDotNet]:

[source,csharp]
----
[Params(1_000_000)]
public int Iterations { get; set; }

private readonly UnsealedClass unsealedType = new UnsealedClass();
private readonly SealedClass sealedType = new SealedClass();

[Benchmark(Baseline = true)]
public void UnsealedType()
{
    for (int i = 0; i < Iterations; i++)
    {
        unsealedType.DoNothing();
    }
}

[Benchmark]
public void SealedType()
{
    for (int i = 0; i < Iterations; i++)
    {
        sealedType.DoNothing();
    }
}

private class BaseType
{
    public virtual void DoNothing() { }
}

private class UnsealedClass : BaseType
{
    public override void DoNothing() { }
}

private sealed class SealedClass : BaseType
{
    public override void DoNothing() { }
}
----

Hardware Configuration:

[source]
----
BenchmarkDotNet=v0.13.5, OS=Windows 10 (10.0.19045.2846/22H2/2022Update)
12th Gen Intel Core i7-12800H, 1 CPU, 20 logical and 14 physical cores
.NET SDK=7.0.203
  [Host]   : .NET 7.0.5 (7.0.523.17405), X64 RyuJIT AVX2
  .NET 5.0 : .NET 5.0.17 (5.0.1722.21314), X64 RyuJIT AVX2
  .NET 6.0 : .NET 6.0.16 (6.0.1623.17311), X64 RyuJIT AVX2
  .NET 7.0 : .NET 7.0.5 (7.0.523.17405), X64 RyuJIT AVX2
----