Add update cache methods to Fetcher

[maxperrimond]

No description provided.

[nickhudkins]

Hi @maxperrimond, it's been a while here, so my apologies.

Two questions:
1.) Are you still actively using Sangria?
2.) Do you have interest in moving this along?

One thing I'd like to understand a bit more is the use case. Could you provide some motivation behind why this change is important, specifically what it allows a user of Sangria to do that is not possible today?

My immediate reaction is that this is highly dependent on the fetcher cache existing ACROSS requests to provide benefit, but it is entirely possible that I am just missing the intention.

Thanks!
Nick