在C#和System.Reactive中，如何用基于事件的类替换基于观察值的类？

using System;
using System.Reactive.Linq;

public class ObservableCounter
{
    private IObservable<int> _observable;

    public ObservableCounter()
    {
        _observable = Observable.Interval(TimeSpan.FromSeconds(1)).Select(i => i);
    }

    public IObservable<int> Numbers => _observable;
}

using System;

public class EventCounter
{
    // 定义一个委托
    public delegate void NumberEventHandler(object sender, NumberEventArgs e);

    // 定义一个事件
    public event NumberEventHandler NumberGenerated;

    private int _currentNumber;

    public EventCounter()
    {
        // 启动一个后台线程来生成数字并触发事件
        System.Threading.Thread thread = new System.Threading.Thread(() =>
        {
            while (true)
            {
                System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1));
                _currentNumber++;
                NumberGenerated?.Invoke(this, new NumberEventArgs(_currentNumber));
            }
        });
        thread.Start();
    }
}

// 自定义事件参数类
public class NumberEventArgs : EventArgs
{
    public int Number { get; }

    public NumberEventArgs(int number)
    {
        Number = number;
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        EventCounter counter = new EventCounter();

        // 订阅事件
        counter.NumberGenerated += (sender, e) =>
        {
            Console.WriteLine("Generated number: " + e.Number);
        };

        // 让程序持续运行，以便我们可以看到事件被触发
        Console.ReadLine();
    }
}