I agree with the others that this is pretty important.
Coming from the MVC version of this function, I had alot of confusion as to why a CancellationToken can't be passed.

Seeing this brought up 3 years ago and is currently marked as "Unplanned" is disheartening...

If anyone else has a work around, I would love to see what you came up with.

Wanted to chime in that we need this too. Since adopting the use of the DataSource extensions, we've discovered that our CancellationToken is passed all the way down only to go unused here, where it's needed most. Obviously, this should pass the token down to the underlying operation so a long-running database query could be canceled, for example. Currently it looks like .ToDataSourceResultAsync() is just a task wrapper for the synchronous .ToDataSourceResult() method.

I'd really like to avoid creating a homegrown library similar to this one, since this already does so much and is a huge help!

Voted and followed.

Any news here? I actually need to cancel queries during grid pagination (from Kendo Angular Grid component)

I think it is a crucial feature, we have few kendo grid (angular) with virtual scroll enabled and we need for sure to cancel old page requests during user interaction to increase performance and also decrease cost (if you think on a cloud solution it is really important)

We're currently in need of this too.
We're sending the serialized DataSourceRequest to the server, so we can use the ToDataSourceResultAsync method, which works awesomely, but since our grids call the OnRead event for every typed letter in the filter boxes, we need to cancel the server queries ourselves. It's a bit stupid to cancel a request, but still having an SQL query run to completion for no reason (double so since it does a query for the total amount of records too).