Get key associated with current data when keepPreviousData is used

[truslew]

Will it be possible to include the key used to get data in the SWRResponse together with the data?

The case is:
We have a setup where we use 2 useSWR hooks where #2 is dependent on the data from #1 and the key used for #1. This is used to show a list of data and some totals that are fetched asynchronously. To avoid flickering, we use the keepPreviousData and onLoadingSlow to keep the old data for a small amount of time before displaying a spinner.

But, useSWR #2 will start fetching data when key used for #1 is changes as this is used for #2 also. And when #1 has fetched the data, #2 will fetch the correct data depending on both data and key from #1.

Had to use data from onLoadingSlow instead of result from useSWR to be able to have data and the corresponding key in sync.