public class StringsTest : PerformanceTest
{
    protected override bool MeasureTestA()
    {
        // string additions using regular string type
        var result = string.Empty;
        for (int i = 0; i < Iterations; i++)
        {
            result = result + '*';
        }
        return true;
    }

    protected override bool MeasureTestB()
    {
        // string additions using stringbuilder
        StringBuilder result = new StringBuilder(Iterations);
        for (int i = 0; i < Iterations; i++)
        {
            result.Append('*');
        }
        return true;
    }

    protected unsafe override bool MeasureTestC()
    {
        // fill string by using pointer operations
        var result = new char[Iterations];
        fixed (char* fixedPointer = result)
        {
            var pointer = fixedPointer;
            for (int i = 0; i < Iterations; i++)
            {
                *(pointer++) = '*';
            }
        }
        return true;
    }
}