meds-processor, p2, s5

HzzoExcelDownloader.cs

public async Task<ISet<HzzoMedsDownloadDto>> Run(ISet<HzzoMedsDownloadDto> meds)
{
  // NOTE: throttle requests in parallel
  var parallelismDegree = 5;
  var waitBetweenRequestsMs = 500;

  var savingItems = new List<Task>();
  var notDownloadedDocs = meds.Where(x => !x.IsAlreadyDownloaded).ToList();

  for (int i = 0; i < notDownloadedDocs.Count; i += parallelismDegree)
  {
    var queuedMeds = meds.Skip(i).Take(parallelismDegree);

    savingItems.AddRange(
      (await Task.WhenAll(queuedMeds.Select(DownloadExcel)))
      .Select(SaveExcel));

    await Task.Delay(waitBetweenRequestsMs);
  }

  Task.WaitAll(savingItems.ToArray());
  return meds;
}