Add event timing

[leofang]

When working on #475 (68c9365) I noticed we surprisingly haven't implemented event-based timing... Looks like an oversight to me because we did spend a lot of time discussing the default of the enabling_timing option and how to retrieve the timing result. This PR adds the implementation, which is also aligned with the cuda::experimental::timed_event treatment:
https://github.com/NVIDIA/cccl/blob/096596b3580d6cb2042fff692e8162d2a0ea356b/cudax/include/cuda/experimental/__event/timed_event.cuh#L90

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[leofang]

/ok to test

[leofang]

/ok to test

[carterbox]

I like the semantics of this implementation. It wouldn't have thought that you could directly subtract two Events to get the difference between them in time, but I like it.

One thing that may be missing is documentation of what happens if timing is not enabled. What is the expected behavior? I suspect the answer is that the difference is zero, but raising an error because we tried to do timing without enabling timing seems more pythonic.

[leofang]

One thing that may be missing is documentation of what happens if timing is not enabled. What is the expected behavior? I suspect the answer is that the difference is zero, but raising an error because we tried to do timing without enabling timing seems more pythonic.

Currently we do raise an exception since the driver API would return an error if the events were created without timing enabled:

cuda.core.experimental._utils.CUDAError: CUDA_ERROR_INVALID_HANDLE: invalid resource handle

So the question is if we want to do an exception chaining and raise, say, RuntimeError with a clearer err msg. @rwgk thoughts?

[leofang]

Currently we do raise an exception since the driver API would return an error if the events were created without timing enabled:

We ensure this exception is raised in commit 8aca468. The discussion for an optional exception chaining is still open.

[carterbox]

If it's possible to catch and reraise the error with a message like "Timing must be enabled in order subtract Events. Events have timing disabled by default." That would be better than "invalid resource handle".

[leofang]

/ok to test

[leofang]

This is ready.

[rwgk]

Seeing the code now, I like the exception chaining approach better than the idea I posted before.

[leofang]

Thanks, Ralf/Daniel!

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