在SignalR 3.0中从任何位置检索中心上下文的最佳方式

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        // 注册SignalR服务
        services.AddSignalR();
        
        // 注册其他服务和依赖项
        // ...
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        // 配置SignalR中间件
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapHub<MyHub>("/myhub");
        });
        
        // 配置其他中间件和路由
        // ...
    }
}

public class MyHub : Hub
{
    private readonly IHubContext<MyHub> _hubContext;

    public MyHub(IHubContext<MyHub> hubContext)
    {
        _hubContext = hubContext;
    }

    public async Task SendMessage(string message)
    {
        await _hubContext.Clients.All.SendAsync("ReceiveMessage", message);
    }
}