[WIP] Memoize refetch in useGet hook

[owinter86]

Why

Addresses #186, refetch is memoized against the same dependency array as the auto fetchData() effect within the package.

[owinter86]

Sorry, I changed my train of thought a few times with this, I think refetch should not depend on anything and be referentially equal on first initialisation, but since the fetchData function is extracted out of the hook, I think I need to create two refetch function to ensure none of the data passed to _fetchData is stale, hence why there is refetch and refetchMemo.

[tonthanhhung]

@owinter86, Could you give some sort description why did you close this PR ?, I think it's quite helpful in many cases

[owinter86]

From what I recall, I closed this as its not a simple solution as I first thought (basic memoization of refetch), retry is returning the fetchData function which is abstracted out of the component, and relies on props and state to be passed to it as arguments, so retry will always need to be updated with the latest versions of state and props, and therefore will always update when fetching new data.

I felt as though the fetchData abstraction would need to be removed and rewritten, so it was to not rely on having those arguments passed to it, I am not sure that this would be in line with how this package was setup, and unfortunately did not have capacity to continue with the PR.

Thankfully the testing suite is nice and robust and caught out those issues identified.

There is probably a straight forward solution that I am missing, but this PR wont solve that. Thats why I closed it.

Sorry I couldn't help out more.