Asp.net Core 中间件几种注册方式

《ASP.NET Core 6 框架解密》总结，笔记：

1.RequestDelegate

RequestDelegate委托对象作为参数调用了WebApplication对象的Run扩展方法。
该扩展方法只是注册了一个中间件，具体点，就是说这个扩展方法用于注册处于管道末端的中间件

　　如下图，主要是几种委托的写法。

RequestDelegate handler = context => context.Response.WriteAsync("Hello,World!");
WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
WebApplication app = builder.Build();
app.Run(handler);
app.Run();

var app = WebApplication.Create(args);
IApplicationBuilder builder = app;
builder.Use(HelloMiddleware)
    .Use(WorldMiddleware);
app.Run();

static RequestDelegate HelloMiddleware(RequestDelegate next) =>
    async httpcontext =>
    {
        await httpcontext.Response.WriteAsync("Hello,");
        await next(httpcontext);
    };

static RequestDelegate WorldMiddleware(RequestDelegate next) =>
    httpcontext => httpcontext.Response.WriteAsync("World!");

var app = WebApplication.Create(args);
IApplicationBuilder builder = app;
builder.Use(HelloMiddleware)
    .Use(WorldMiddleware);
app.Run();

//Func<HttpContext,RequestDelegate,Task>
//Func<HttpContext,Func<Task>,Task>
static async Task HelloMiddleware(HttpContext context, RequestDelegate next)
{
    await context.Response.WriteAsync("Hello,");
    await next(context);
}

static Task WorldMiddleware(HttpContext context, RequestDelegate next) =>
    context.Response.WriteAsync("World!");