.NET Core 项目添加对 .NET Framework 项目的引用。为什么有可能

csharp
// CoreLibrary.cs
using System;
namespace CoreLibrary
{
    public class MyCoreClass
    {
        public void DoSomething()
        {
            Console.WriteLine("Doing something in .NET Core");
        }
    }
}

csharp
// FrameworkApp.cs
using CoreLibrary;
namespace FrameworkApp
{
    class Program
    {
        static void MAIn(string[] args)
        {
            MyCoreClass myCoreClass = new MyCoreClass();
            myCoreClass.DoSomething();
        }
    }
}