GenerateRandomString

        static string GenerateRandomString(int count = 10000,bool endnl = false) {
            Random rand = new Random(Guid.NewGuid().ToString().GetHashCode());
            return GenerateRandomString(rand,count,endnl);
        }
        static string GenerateRandomString(Random rand,int count = 10000,bool endnl = false) {
            StringBuilder sb = new StringBuilder(count);
            for(int i = 0;i < count;i++)
                sb.Append((char)('a' + rand.Next(0,26)));
            if(endnl)
                sb.AppendLine();
            return sb.ToString();
        }