ValueTupleBenchmarks.cs

public class TypeTuple : IEquatable<TypeTuple>
{
    public bool Equals(TypeTuple other)
    {
        if (ReferenceEquals(null, other)) return false;
        return EqualityComparer<Type>.Default.Equals(this.Source, other.Source) &&
                EqualityComparer<Type>.Default.Equals(this.Destination, other.Destination);
    }

    public override bool Equals(object obj)
    {
        return Equals(obj as TypeTuple);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            return ((Source?.GetHashCode() ?? 0) << 16) ^ ((Destination?.GetHashCode() ?? 0) & 65535);
        }
    }

    public static bool operator ==(TypeTuple left, TypeTuple right)
    {
        if (ReferenceEquals(null, left)) return ReferenceEquals(null, right);
        return left.Equals(right);
    }

    public static bool operator !=(TypeTuple left, TypeTuple right)
    {
        if (ReferenceEquals(null, left)) return !ReferenceEquals(null, right);
        return !left.Equals(right);
    }

    public Type Source { get; }
    public Type Destination { get; }

    public TypeTuple(Type source, Type destination)
    {
        this.Source = source;
        this.Destination = destination;
    }
}

public class TypeTuple2<T1, T2> : IEquatable<TypeTuple2<T1, T2>>
{
    public bool Equals(TypeTuple2<T1, T2> other)
    {
        if (ReferenceEquals(null, other)) return false;
        return EqualityComparer<T1>.Default.Equals(this.Source, other.Source) &&
                EqualityComparer<T2>.Default.Equals(this.Destination, other.Destination);
    }

    public override bool Equals(object obj)
    {
        return Equals(obj as TypeTuple2<T1, T2>);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            return ((Source?.GetHashCode() ?? 0) << 16) ^ ((Destination?.GetHashCode() ?? 0) & 65535);
        }
    }

    public static bool operator ==(TypeTuple2<T1, T2> left, TypeTuple2<T1, T2> right)
    {
        if (ReferenceEquals(null, left)) return ReferenceEquals(null, right);
        return left.Equals(right);
    }

    public static bool operator !=(TypeTuple2<T1, T2> left, TypeTuple2<T1, T2> right)
    {
        if (ReferenceEquals(null, left)) return !ReferenceEquals(null, right);
        return !left.Equals(right);
    }

    public T1 Source { get; }
    public T2 Destination { get; }

    public TypeTuple2(T1 source, T2 destination)
    {
        this.Source = source;
        this.Destination = destination;
    }
}

public class StructTypeTuple : IEquatable<StructTypeTuple>
{
    public bool Equals(StructTypeTuple other)
    {
        if (ReferenceEquals(null, other)) return false;
        return Source == other.Source && Destination == other.Destination;
    }

    public override bool Equals(object obj)
    {
        return Equals(obj as StructTypeTuple);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            return ((Source?.GetHashCode() ?? 0) << 16) ^ ((Destination?.GetHashCode() ?? 0) & 65535);
        }
    }

    public static bool operator ==(StructTypeTuple left, StructTypeTuple right)
    {
        if (ReferenceEquals(null, left)) return ReferenceEquals(null, right);
        return left.Equals(right);
    }

    public static bool operator !=(StructTypeTuple left, StructTypeTuple right)
    {
        if (ReferenceEquals(null, left)) return !ReferenceEquals(null, right);
        return !left.Equals(right);
    }

    public Type Source { get; }
    public Type Destination { get; }

    public StructTypeTuple(Type source, Type destination)
    {
        this.Source = source;
        this.Destination = destination;
    }
}

class CustomerDto
{
        
}

class Customer
{
}

[MemoryDiagnoser]
public class DelegateStorageRetrieve
{
    private Dictionary<(Type, Type), Delegate> dictTupleStorage = new Dictionary<(Type, Type), Delegate>();
    private Dictionary<TypeTuple, Delegate> dictTypeTupleStorage = new Dictionary<TypeTuple, Delegate>();
    private Dictionary<TypeTuple2<Type, Type>, Delegate> genDictTypeTupleStorage = new Dictionary<TypeTuple2<Type, Type>, Delegate>();
    private Dictionary<System.Tuple<Type, Type>, Delegate> regularDictTypeTupleStorage = new Dictionary<System.Tuple<Type, Type>, Delegate>();
    private Dictionary<StructTypeTuple, Delegate> dictStructTypeTupleStorage = new Dictionary<StructTypeTuple, Delegate>();

    [GlobalSetup]
    public void Init()
    {
        Func<CustomerDto, Customer> activator = (x) => new Customer();
        dictTupleStorage.Add((typeof(CustomerDto), typeof(Customer)), activator);
        dictTypeTupleStorage.Add(new TypeTuple(typeof(CustomerDto), typeof(Customer)), activator);
        genDictTypeTupleStorage.Add(new TypeTuple2<Type, Type>(typeof(CustomerDto), typeof(Customer)), activator);
        dictStructTypeTupleStorage.Add(new StructTypeTuple(typeof(CustomerDto), typeof(Customer)), activator);
        regularDictTypeTupleStorage.Add(new Tuple<Type, Type>(typeof(CustomerDto), typeof(Customer)), activator);
    }

    [Benchmark]
    public Delegate DictionaryTuple()
    {
        var key = (typeof(CustomerDto), typeof(Customer));
        return dictTupleStorage[key];
    }

    [Benchmark]
    public Delegate DictionaryTypeTuple()
    {
        var key = new TypeTuple(typeof(CustomerDto), typeof(Customer));
        return dictTypeTupleStorage[key];
    }

    [Benchmark]
    public Delegate DictionaryGenericTypeTuple()
    {
        var key = new TypeTuple2<Type, Type>(typeof(CustomerDto), typeof(Customer));
        return genDictTypeTupleStorage[key];
    }

    [Benchmark]
    public Delegate DictionaryStructTypeTuple()
    {
        var key = new StructTypeTuple(typeof(CustomerDto), typeof(Customer));
        return dictStructTypeTupleStorage[key];
    }

    [Benchmark]
    public Delegate DictionarySystemTuple()
    {
        var key = new Tuple<Type, Type>(typeof(CustomerDto), typeof(Customer));
        return regularDictTypeTupleStorage[key];
    }
}

// Results
/*
                     Method |      Mean |     Error |    StdDev |  Gen 0 | Allocated |
--------------------------- |----------:|----------:|----------:|-------:|----------:|
            DictionaryTuple | 101.18 ns | 0.4298 ns | 0.3810 ns |      - |       0 B |
        DictionaryTypeTuple |  72.63 ns | 0.2599 ns | 0.2304 ns | 0.0101 |      32 B |
 DictionaryGenericTypeTuple |  99.30 ns | 1.7590 ns | 1.6454 ns | 0.0101 |      32 B |
  DictionaryStructTypeTuple |  48.71 ns | 0.1830 ns | 0.1429 ns | 0.0101 |      32 B |
      DictionarySystemTuple | 132.99 ns | 0.4867 ns | 0.3800 ns | 0.0100 |      32 B |
*/