using is ommited

Controllers/SCUController.cs

@@ -30,12 +30,11 @@ namespace SendFileWebapi.Controllers
             inputsDto.FileNames.ToObservable()
                 .Select(fileName => Observable.FromAsync(async () =>
             {
-                using (var stream = fileName.OpenReadStream())
-                {
+                var stream = fileName.OpenReadStream();
                 var request = new Dicom.Network.DicomCStoreRequest(await DicomFile.OpenAsync(stream));
                 await client.AddRequestAsync(request);
                 await client.SendAsync();
-                }
+                stream.Dispose();
             }).Select(x => fileName.FileName).Catch<string, Exception>(exp => throw new Exception($"failed to send: {fileName}, with error:{exp.Message}")))
                 .Concat()
                 .Subscribe(