private IAsyncEnumerable <Message> StreamMessages(CancellationToken stopToken) =>
new AsyncEnumerable <Message>(async yield =>
{
while (!stopToken.IsCancellationRequested)
{
try
{
var message = await _messageHub.GetMessage(stopToken)
.ContinueWith(task => task.IsCanceled ? null : task.Result);
if (message == null)
{
break;
}
await yield.ReturnAsync(message);
}
catch (OperationCanceledException)
{
break;
}
}
});