.NET Core SqlConnection ConnectRetryCount not work?

netcore_Program.cs

using System;
using System.Data.SqlClient;
using System.Diagnostics;

namespace NETCore
{
    class Program
    {
        static string connstr = @"Data Source=localhost;Initial Catalog=master;Integrated Security=True;Connect Timeout=5;Encrypt=False;";

        static void Main(string[] args)
        {
            Test_ConnectRetry();
            Console.ReadKey();
        }
        static void Test_ConnectRetry()
        {
            Stopwatch s = null;
            try
            {
                using (var conn = new SqlConnection(connstr + "ConnectRetryCount=5;ConnectRetryInterval=5;"))
                using (var cmd = new SqlCommand(@"select 1", conn))
                {
                    conn.Open();

                    Console.WriteLine(cmd.ExecuteScalar());
                    Console.WriteLine("net stop <sql server service>");
                    Console.ReadKey(); // manually SQL Server service stop
                    Console.WriteLine("SQL Server Service stoped!");
                    s = Stopwatch.StartNew();

                    cmd.ExecuteScalar();

                    Console.WriteLine("not run");
                }
            }
            catch (Exception ex)
            {
                s.Stop();
                Console.WriteLine(ex.Message);
                Console.WriteLine(s.ElapsedMilliseconds); // about 7000
            }
        }
    }
}

netframework_Program.cs

using System;
using System.Data.SqlClient;
using System.Diagnostics;

namespace NETFramework472
{
    class Program
    {
        static string connstr = @"Data Source=localhost;Initial Catalog=master;Integrated Security=True;Connect Timeout=5;Encrypt=False;";

        static void Main(string[] args)
        {
            Test_ConnectRetry();
            Console.ReadKey();
        }
        static void Test_ConnectRetry()
        {
            Stopwatch s = null;
            try
            {
                using (var conn = new SqlConnection(connstr + "ConnectRetryCount=5;ConnectRetryInterval=5;"))
                using (var cmd = new SqlCommand(@"select 1", conn))
                {
                    conn.Open();

                    Console.WriteLine(cmd.ExecuteScalar());
                    Console.WriteLine("net stop <sql server service>");
                    Console.ReadKey(); // manually SQL Server service stop
                    Console.WriteLine("SQL Server Service stoped!");
                    s = Stopwatch.StartNew();

                    cmd.ExecuteScalar();

                    Console.WriteLine("not run");
                }
            }
            catch (Exception ex)
            {
                s.Stop();
                Console.WriteLine(ex.Message);
                Console.WriteLine(s.ElapsedMilliseconds); // over 30000
            }
        }
    }
}

.NET Framework 4.7.2 + System.Data.SqlClient 4.7.0
.NET Core 3.0 + System.Data.SqlClient 4.7.0