Pattern Matching in c#

PatternMatch.cs

public static class Match
{
    public static PatternMatch<T, R> With<T, R>(T value)
    {
        return new PatternMatch<T, R>(value);
    }

    public struct PatternMatch<T, R>
    {
        private readonly T _value;
        private R _result;

        private bool _matched;

        public PatternMatch(T value)
        {
            _value = value;
            _matched = false;
            _result = default(R);
        }

        public PatternMatch<T, R> When(Func<T, bool> condition, Func<R> action)
        {
            if (!_matched && condition(_value))
            {
                _result = action();
                _matched = true;
            }

            return this;
        }

        public PatternMatch<T, R> When<C>(Func<C, R> action)
        {
            if (!_matched && _value is C)
            {
                _result = action((C)(object)_value);
                _matched = true;
            }
            return this;
        }


        public PatternMatch<T, R> When<C>(C value, Func<R> action)
        {
            if (!_matched && value.Equals(_value))
            {
                _result = action();
                _matched = true;
            }
            return this;
        }


        public R Result => _result;

        public R Default(Func<R> action)
        {
            return !_matched ? action() : _result;
        }
    }
}


// examples:

var result = Match.With<IFoo, int>(new Foo() { A = 5 })
    .When<IFoo>(foo => foo.A)
    .When<IBar>(bar => bar.B)
    .When<string>(Convert.ToInt32)
    .Result;
Assert.Equal(5, result);


var result = Match.With<int, string>(n)
    .When(x => x > 100, () => "n>100")
    .When(x => x > 10, () => "n>10")
    .Default(() => "");
Assert.Equal("n>10", result);

 var result = Match.With<int, string>(5)
     .When(1, () => "1")
     .When(5, () => "5")
     .Default(() => "e");

 Assert.Equal("5", result);

Sample usage?