public DayOfWeek EnumParse() => (DayOfWeek)Enum.Parse(typeof(DayOfWeek), "Thursday");

//IEnumerable<int> _tenMillionToZero = Enumerable.Range(0, 10_000_000).Reverse();

public int LinqOrderBySkipFirst() => _tenMillionToZero.OrderBy(i => i).Skip(4).First();

//byte[] _raw = new byte[100 * 1024 * 1024];
//for (int index = 0; index < _raw.Length; index++) _raw[index] = (byte)index;

public byte[] Sha256() => _sha256.ComputeHash(_raw);

// static string _s = "abcdefghijklmnopqrstuvwxyz";

public bool StringStartsWith()
{
    var data = false;
    for (int i = 0; i < 100_000_000; i++)
    {
        data = _s.StartsWith("abcdefghijklmnopqrstuvwxy-", StringComparison.Ordinal);
    }
    return data;
}

// _bingIntToParse = string.Concat(Enumerable.Repeat("654719003", 50));

public BigInteger ParseBigInt() => BigInteger.Parse(_bingIntToParse);

//var _books = new List<Book>();
//for (int i = 0; i < 1_00000; i++)
//{
//    string id = i.ToString();
//    _books.Add(new Book { Name = id, Id = id });
//}
    
public object Deserialize()
{    
    var formatter = new BinaryFormatter();
    var mem = new MemoryStream();
    formatter.Serialize(mem, _books);
    mem.Position = 0;

    return formatter.Deserialize(mem);
}

_regexEmail = new Regex(@"[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?", RegexOptions.Compiled);

 _regexEmail.IsMatch(_commonInput);

_regexStrongPassword = new Regex(@"^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[a-zA-Z]).{8,}$", RegexOptions.Compiled);

_regexStrongPassword.IsMatch(_commonInput);

_regexSpanSearching = new Regex("([ab]cd|ef[g-i])jklm", RegexOptions.Compiled);

_regexSpanSearching.IsMatch(_commonInput);

_regexBackTracking = new Regex("a*a*a*a*a*a*a*b", RegexOptions.Compiled);;

_regexBackTracking.IsMatch("aaaaaaaaaaaaaaaaaaaaa");

using (var fileStream = new FileStream(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize: 4096, useAsync: true))
{
    while (await fileStream.ReadAsync(_buffer, 0, _buffer.Length) > 0)
    {
    }
}

using (var fileStream = new FileStream(_fileName, FileMode.Create, FileAccess.Write, FileShare.Read, bufferSize: 4096, useAsync: true))
{
    for (int i = 0; i < FileSize / _buffer.Length; i++)
    {
        await fileStream.WriteAsync(_buffer, 0, _buffer.Length);
    }
}