Adding Timeout Property to DurableHttpRequest

[bachuv]

These changes resolve #1278 by adding a Timeout property to DurableHttpRequest. This property defines the timeout for each individual HTTP request. This timeout applies to each asynchronous polling request too.

[bachuv]

To make this more accurate, it could be catch (OperationCanceledException ex) when (cts.Token.IsCancellationRequested) (added the commented out part). This way we know that the exception came when a cancel request was sent to CancellationTokenSource. The only issue with this is adding tests that mirror the action of cancelling a CancellationTokenSource. The Mock<HttpMessageHandler> Setup call takes ItExpr.IsAny<CancellationToken>() and the test would need the CancellationTokenSource to cancel the task, not the CancellationToken.

I saw that that ItExpr.IsAny() could evaluate conditions, but didn't see anything about sending in another object to manipulate. Let me know if there's a way to pass in a CancellationTokenSource using Moq.

This is how the HttpMessageHandler is mocked right now:

var handlerMock = new Mock<HttpMessageHandler>(MockBehavior.Strict);
handlerMock 
  .Protected()
  .Setup<Task<HttpResponseMessage>>("SendAsync", ItExpr.IsAny<HttpRequestMessage>(), ItExpr.IsAny<CancellationToken>())
  .ReturnsAsync(httpResponseMessage);

[ConnorMcMahon]

Answered some questions and gave some feedback, but there is still some stuff that needs to be clarified.

[cgillum]

Adding a bit of my own feedback here.

[ConnorMcMahon]

Looks good. I have a small nit, but not a blocker. It's up to you whether you want to fix it before merging.

[cgillum]

Resetting my approval status. No blockers from me.