feat: Support for name client to given provider

[benjiro]

This PR

Adds support for mapping name clients to a given provider.

• Preserves backward compatibility with existing clients

Related Issues

Refs: Refs open-feature/ofep#56
Fixes: #131

Notes

N/A

Follow-up Tasks

• Update documentation

How to test

Testing is covered by the unit tests added in the PR

[codecov]

Codecov Report

Merging #129 (abaea88) into main (9152d63) will increase coverage by 0.10%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     open-feature/dotnet-sdk#129      +/-   ##
==========================================
+ Coverage   94.54%   94.64%   +0.10%     
==========================================
  Files          20       20              
  Lines         532      542      +10     
  Branches       37       39       +2     
==========================================
+ Hits          503      513      +10     
  Misses         16       16              
  Partials       13       13              

Impacted Files	Coverage Δ
src/OpenFeature/Api.cs	100.00% <100.00%> (ø)
src/OpenFeature/OpenFeatureClient.cs	98.70% <100.00%> (-0.05%)	⬇️

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[kinyoklion]

I am not sure about the "or more client names." part of this.

Which implies to me:

var provider = new TestProvider();

openFeature.SetProvider("a", provider);
openFeature.SetProvider("b", provider);

[kinyoklion]

(Which will need more consideration with init/shutdown potentially.)

[toddbaert]

Do you have concerns with mapping the same provider instance to 2 names? What's the risk you see here? Maybe we need to spec something additional?

[kinyoklion]

@toddbaert

Basic case.

var provider1 = new TestProvider();

openFeature.SetProvider("a",  provider1);

// Call init on provider1?

openFeature.SetProvider("a",  new TestProvider());

// Call shutdown on provider 1?

// Call init on new provider.

Two Names Scenario 1.

var provider = new TestProvider();

openFeature.SetProvider("a", provider);

// Call init on provider?

openFeature.SetProvider("b", provider);

// Provider already has init called. Do we call it again?

Two Names Scenario 2.

var provider1 = new TestProvider();

openFeature.SetProvider("a", provider1);
openFeature.SetProvider("b", provider1);

openFeature.SetProvider("b",  new TestProvider());

// We don't want to shutdown provider1, because it is still registered to "b".

[benjiro]

I've added this scenario to the tests cases.

This is an interesting thought about the init/shutdown, I haven't yet had a look at the spec for it but I would think it only calls shutdown if there are zero references to the object. I'll create a issue for this and lets continue the discussion under that

[benjiro]

https://github.com/open-feature/dotnet-sdk/issues/132

[kinyoklion]

Approved with comment on test.

[toddbaert]

@benjiro I hope you don't mind, I created a new standalone issue and linked it so that the whole 0.6.0 issue isn't closed.