“HttpRequest”不包含“CreateResponse”的定义，也不包含可访问的扩展方法

public class CustomMiddleware
{
    private readonly RequestDelegate _next;

    public CustomMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        // 检查请求路径或其他条件
        if (context.Request.Path == "/custom")
        {
            // 创建响应
            context.Response.ContentType = "text/plain";
            await context.Response.WriteAsync("This is a custom response.");
            return; // 注意这里直接返回，不再调用 _next(context)
        }

        // 如果不是自定义路径，继续处理请求
        await _next(context);
    }
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    app.UseMiddleware<CustomMiddleware>();

    app.UseRouting();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
    });
}