using System;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        ReadOnlySpan<byte> r = stackalloc byte[] { 52, 48, 48, 55, 48 };

        var sw = new Stopwatch();

        int result = 0;

​

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result =  Test1(r);

        sw.Stop();

        Console.WriteLine($"Test1 took {sw.ElapsedMilliseconds}ms {result}");

​

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result = Test2(r);

        sw.Stop();

        Console.WriteLine($"Test2 took {sw.ElapsedMilliseconds}ms {result}");

​

    }

​

    public static int Test1(ReadOnlySpan<byte> source)

    {

        int answer = 0;

        int index = 0;

        int c = source[index];

        answer = c - '0';

        while (true)

        {

            index++;

            if ((uint)index >= (uint)source.Length)

                break;

            c = source[index];

            answer = answer * 10 + c - '0';

        }

         return answer;

    }

    public static int Test2(ReadOnlySpan<byte> data)

    {

        if (System.Buffers.Text.Utf8Parser.TryParse(data, out int value, out int bytes))

        {

            return(value);

        }   

        else

            return(0);

    }

}