WebApi client disconnection

detect_disconnect.cs

        [HttpGet(Name = "GetWeatherForecast")]
        public async Task<IEnumerable<WeatherForecast>> Get()
        {
            //pass this around to long running tasks
            CancellationToken cancellationToken = HttpContext.RequestAborted;
            if (cancellationToken.IsCancellationRequested)
            {
                throw null!; // or whatever you want to do
            }
            return await DoItSlowly(++_callerCount, cancellationToken);
        }

        private async Task<IEnumerable<WeatherForecast>> DoItSlowly(int callerCount,
            CancellationToken cancellationToken)
        {
            List<WeatherForecast> l = new List<WeatherForecast>();
            for (int i = 0; i < 5; i++)
            {
                cancellationToken.ThrowIfCancellationRequested();
                _logger.LogWarning($"Caller id = {callerCount}, index = {i}");
                await Task.Delay(1000);

                l.Add(new WeatherForecast
                {
                    Date = DateTime.Now.AddDays(i),
                    TemperatureC = Random.Shared.Next(-20, 55),
                    Summary = Summaries[Random.Shared.Next(Summaries.Length)]
                });
            }

            return l.ToArray();
        }