[CSharp-Netcore][Go] Optimize time taken to generate CSharp code

[vvb]

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This PR greatly reduces the time taken for Csharp-netcore code generation.
toModelName() method is invoked numerous number of times and it was accummulating to a lot of time.
This PR adds memoization to CSharp and DefaultCodeGen toModelName() methods.
This has reduced the C# SDK generation time for our rather large openapi spec from ~2 hours to 4 mins.
This has reduced the Golang SDK generation time for our rather large openapi spec from ~1h30m hours to 4 mins.

The generated code is the same as before.

spec: https://cdn.intersight.com/components/an-apidocs/1.0.9-4430/model/intersight-openapi-v3-1.0.9.4430.yaml

[vvb]

/cc @wing328 @mandrean @frankyjuang @shibayan @Blackclaws @lucamazzanti

[Blackclaws]

Just out of curiosity if you're seeing generation times of 2 hours how large is your api definition file? I've been running the generator on what I would consider intermediate sized apis and it never took more than a minute.

[vvb]

Just out of curiosity if you're seeing generation times of 2 hours how large is your api definition file? I've been running the generator on what I would consider intermediate sized apis and it never took more than a minute.

Our spec is very large, over 350k lines, 5000+ model objects. You can check it out at https://cdn.intersight.com/components/an-apidocs/1.0.9-4430/model/intersight-openapi-v3-1.0.9.4430.yaml

[Blackclaws]

Ok, yeah that is indeed a spec size that not a lot of people will have. That being said I have no issue with this pull request and it looks good to me, performance enhancements are always welcome even if they are mostly relevant to edge cases :)

[Blackclaws]

I'm wondering if this seems to be an issue in multiple generators, whether this caching shouldn't be going into the default codegen somehow

[vvb]

I'm wondering if this seems to be an issue in multiple generators, whether this caching shouldn't be going into the default codegen somehow

so my initial fix was that - 8452565 But after some pointers from @wing328 it was clear that toModelName() is also invoked at many other places and so a better fix was to memoize toModelName itself.

[devhl-labs]

If it took two hours before, how long does it take after this change?

[wing328]

I'm wondering if this seems to be an issue in multiple generators, whether this caching shouldn't be going into the default codegen somehow

Good point. I'll see what I can do to address the problem in the default codegen.

[wing328]

If it took two hours before, how long does it take after this change?

Down to a few minutes if I'm not mistaken.

[vvb]

If it took two hours before, how long does it take after this change?

1h56m -> 4m

[wing328]

LGTM. I may submit another PR later to try to address similar problem for all generators.