Transform objects in shared informers

[howardjohn]

kubernetes/kubernetes#107507 has possibly huge impacts for us to allow us to transform objects 1x at the lowest level. This can reduce memory usage and redundant conversions

[dddddai]

I think we can work on this now as #38721 is merged, and I took a try, but I found it's a little bit risky because we have to find out all necessary fields where we could possibly miss some of them

@howardjohn Do you think it's fair enough to transform objects like this?

[howardjohn]

Yeah TBH even though this was my idea I am a bit skeptical its worth the cost. Its something to keep in mind, but may be better suited for objects that we only need a tiny subset but are very large. For example, if we just needed the list of versions for CRDs or something (hypothetical - we don't have that use case).

[dddddai]

How about stripping unnecessary fields(like metadata.managedFields for all resources, it's large and I don't think we ever use it) rather than retaining necessary ones? I think it's much easier and could save memory with few code changes