✅ How to create char[] faster?

[MemoryDiagnoser(true)]
public class Generator
{
    [Benchmark]
    public char[] StartGeneration1()
    {
        var random = new Random();

        Span<char> str = stackalloc char[20];

        for (var i = 0; i < 20; i++)
            str[i] = ((char)(random.Next(26) + 'a'));

        return str.ToArray();
    }

    [Benchmark]
    public char[] StartGeneration2()
    {
        var random = new Random();

        var str = new char[20];

        for (var i = 0; i < 20; i++)
            str[i] = (char)(random.Next(26) + 'a');

        return str;
    }
}