如何读取使用NpgSql、c#发送的实际查询和接收的数据？

using Npgsql;
using System;

class Program
{
    static void Main()
    {
        string connString = "Host=myserver;Username=mylogin;Password=mypassword;Database=mydatabase";
        using (var conn = new NpgsqlConnection(connString))
        {
            conn.Open();
            string sql = "SELECT * FROM mytable";
            using (var cmd = new NpgsqlCommand(sql, conn))
            {
                using (var reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        Console.WriteLine(reader["column_name"]);
                    }
                }
            }
        }
    }
}

using Npgsql;
using System;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        string connString = "Host=myserver;Username=mylogin;Password=mypassword;Database=mydatabase";
        using (var conn = new NpgsqlConnection(connString))
        {
            await conn.OpenAsync();
            string sql = "SELECT * FROM mytable";
            using (var cmd = new NpgsqlCommand(sql, conn))
            {
                using (var reader = await cmd.ExecuteReaderAsync())
                {
                    while (await reader.ReadAsync())
                    {
                        Console.WriteLine(reader["column_name"]);
                    }
                }
            }
        }
    }
}