Startup.cs

public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IHostApplicationLifetime hostApplicationLifetime)
{
    // ...
    
    hostApplicationLifetime.ApplicationStarted.Register(() => { });
    hostApplicationLifetime.ApplicationStopping.Register(() =>
    {
        var rabbitMqClient = app.ApplicationServices.GetRequiredService<IRabbitMQClient>();
        rabbitMqClient.CloseConnection();
    });
}