[Proposal] Introduce OutcomeArguments

[martintmk]

Details on the issue fix or feature implementation

Came up in the API review.

These could simplify the delegate definition from:

new ResilienceStrategyBuilder<HttpResponseMessage>()
    .AddRetry(new RetryStrategyOptions<HttpResponseMessage>
    {
        ShouldRetry = (outcome, args)  => outcome switch
        {
            { Exception: HttpRequestException } => PredicateResult.True,
            { Result: HttpResponseMessage response } when !response.IsSuccessStatusCode => PredicateResult.True,
            _ => PredicateResult.False
        }
    });

To:

new ResilienceStrategyBuilder<HttpResponseMessage>()
    .AddRetry(new RetryStrategyOptions<HttpResponseMessage>
    {
        ShouldRetry = outcome => outcome switch
        {
            { Exception: HttpRequestException } => PredicateResult.True,
            { Result: HttpResponseMessage response } when !response.IsSuccessStatusCode => PredicateResult.True,
            _ => PredicateResult.False
        }
    });

Slightly simpler syntax at expense of one extra type. Would still allow us to pass the individual arguments to telemetry. The IResilienceArguments interface won't have much use anymore.

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[martintmk]

@martincostello , @joelhulen what's your opinion here? Should I give this a shot?

[martincostello]

Seems OK to me.

[codecov]

Codecov Report

Merging #1245 (30381b9) into main (2201aaf) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1245      +/-   ##
==========================================
+ Coverage   82.81%   82.85%   +0.04%     
==========================================
  Files         265      261       -4     
  Lines        6105     6120      +15     
  Branches      967      967              
==========================================
+ Hits         5056     5071      +15     
  Misses        844      844              
  Partials      205      205              

Flag	Coverage Δ
linux	?
macos	82.85% <100.00%> (+0.04%)	⬆️
windows	?

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Impacted Files	Coverage Δ
...ack/FallbackResilienceStrategyBuilderExtensions.cs	100.00% <ø> (ø)
....Core/Strategy/ResilienceStrategyBuilderContext.cs	100.00% <ø> (ø)
...rc/Polly.Core/Timeout/TimeoutResilienceStrategy.cs	100.00% <ø> (ø)
src/Polly.Extensions/Telemetry/EnrichmentUtil.cs	100.00% <ø> (ø)
...CircuitBreaker/CircuitBreakerResilienceStrategy.cs	100.00% <100.00%> (ø)
...re/CircuitBreaker/CircuitBreakerStrategyOptions.cs	100.00% <100.00%> (ø)
...ircuitBreaker/Controller/CircuitStateController.cs	100.00% <100.00%> (ø)
...ly.Core/CircuitBreaker/OnCircuitClosedArguments.cs	100.00% <100.00%> (ø)
...ly.Core/CircuitBreaker/OnCircuitOpenedArguments.cs	100.00% <100.00%> (ø)
src/Polly.Core/Fallback/FallbackHandler.Handler.cs	100.00% <100.00%> (ø)
... and 36 more