.net core named httpclient, throttle rate, semaphore, semaphoreslim, task, async, asynchronous,

ThrottledHttpClient.cs

public class ThrottledHttpClient : IThrottledHttpClient
{
    private readonly HttpClient _httpClient;
    private readonly string _baseUrl = @"http://localhost:5000/api";

    public ThrottledHttpClient(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }

    public async Task<PrimeNumberResult[]> GetPrimeNumberResults(
      List<long> numbers, 
      int requestLimit = 2, 
      int limitingPeriodInSeconds = 1)
    {
        var throttler = new SemaphoreSlim(requestLimit);
        var tasks = numbers.Select(async n =>
        {
            await throttler.WaitAsync();

            var task = _httpClient.GetStringAsync($"{_baseUrl}/values/isPrime?number={n}");
            _ = task.ContinueWith(async s =>
            {
                await Task.Delay(1000 * limitingPeriodInSeconds);
                Console.WriteLine($"\t\t {n} waiting");
                throttler.Release();
            });
            try
            {
                var isPrime = await task;
                Console.WriteLine($"{n}");
                return new PrimeNumberResult(n, isPrime);
            }
            catch (HttpRequestException)
            {
                Console.WriteLine($"\t\t\t {n} error out");
                return new PrimeNumberResult(n, "NA");
            }
        });
        return await Task.WhenAll(tasks);
    }
}