异步运行的任务，即使 Main 方法未声明为异步

问：

我写了下面的代码，忘记将 Main 方法声明为异步，所以我的猜测是 and 任务应该同步运行。producerconsumer

using System.Collections.Concurrent;

namespace MainProgram;

public class Program
{
    public static void Main(string[] args)
    {
        using var intCollection = new BlockingCollection<int>();
        int sum = 0;

        Task.Run(() =>
        {
            Console.WriteLine("Running Producer");
            Thread.Sleep(1000);
            for (int i = 0; i < 10; i++)
            {
                intCollection.Add(i);

                Console.WriteLine(i);
            }

            intCollection.CompleteAdding();
        });

        Task.Run(() =>
        {
            Console.WriteLine("Running Consumer");
            Thread.Sleep(1000);
            while (!intCollection.IsCompleted)
            {
                sum += intCollection.Take();
                Console.WriteLine("Thingi Thingi");
            }
        });

        Console.WriteLine("aaabbb");
        Console.ReadLine();
    }
}

但此代码的输出如下所示：

aaabbb
Running Producer
Running Consumer
0
Thingi Thingi
1
Thingi Thingi
2
Thingi Thingi
3
Thingi Thingi
4
Thingi Thingi
5
Thingi Thingi
6
Thingi Thingi
7
8
9
Thingi Thingi
Thingi Thingi
Thingi Thingi

这让我感到惊讶，因为这些任务似乎是异步运行的。有人可以向我解释一下吗？