LogRequest is not logging the correct start-time

[fgheysels]

This is related to arcus-azure/arcus.webapi#310

When calling LogRequest, the timestamp at which the request was started, is not correctly logged. (See the related issue for more detailed information).

This is because the LogRequest method does not contain a parameter that represents the startDateTime, and further up the chain, DateTimeOffset.UtcNow is used for determining the start-date of the request, which is obviously wrong, as the time at which you call this LogRequest method, is not necessarily at the time the request starts.

To fix this, we need to pass in the correct request-starttime to the LogRequest method. There are different approaches for this:

• add yet another parameter to the LogRequest method which represents the start-time of the request. Drawback of this approach is that the method signature becomes bloated. Existing LogRequest overloads can call the newly introduced version and pass in DateTimeOffset.UtcNow as start-time. However, these existing methods should be marked as obsolete imho.

• Instead of passing in a Timespan parameter to represent the duration, we could pass in a DurationMeasurement type. We would then also need to extend the DurationMeasurement so that it contains a StartedAt or StartDateTime property which returns the start-timestamp of the measurement. Drawback of this solution is that people need to pass in a DurationMeasurement, and that might not always be available. (This can offcourse be solved by making sure that we can instantiate DurationMeasurement instances by passing in a DateTimeOffset and a Timespan when constructing it. (Either via a constructor or via a factory method).

• We can pass - in the start-datetime as a property in the context parameter, but that is just implicit and not favorable.

[stijnmoreels]

I think the draw-back of using DurationMeasurement is wrong here bc it already contains a StartTime/Duration so we can create overloads with that type and be done with it 🥳 .