Add event for when Eureka registry is updated

[macsux]

Adds support for #761

[TimHess]

/azp run Steeltoe.All

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[TimHess]

Given the location of the change it's not immediately clear to me how somebody would take advantage of this change, can you provide an example of what you expect that'd look like?

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[codecov]

Codecov Report

Merging #765 (3d65069) into main (947dfb0) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #765      +/-   ##
==========================================
+ Coverage   74.22%   74.24%   +0.02%     
==========================================
  Files        1306     1306              
  Lines       45540    45540              
  Branches     8953     8953              
==========================================
+ Hits        33802    33812      +10     
+ Misses       9235     9225      -10     
  Partials     2503     2503              

Impacted Files	Coverage Δ
src/Discovery/src/Eureka/DiscoveryClient.cs	56.25% <ø> (ø)
...rc/RabbitMQ/Connection/CachingConnectionFactory.cs	58.46% <0.00%> (-0.09%)	⬇️
...gement/src/EndpointBase/ThreadDump/ThreadDumper.cs	68.87% <0.00%> (+0.82%)	⬆️
...n/src/Common/Converter/GenericConversionService.cs	75.54% <0.00%> (+1.08%)	⬆️
.../StreamBase/Binder/AbstractMessageChannelBinder.cs	68.45% <0.00%> (+1.43%)	⬆️
....MetricsStreamCore/RabbitMetricsStreamPublisher.cs	15.38% <0.00%> (+2.56%)	⬆️
...StreamBase/Binding/AbstractBindableProxyFactory.cs	72.00% <0.00%> (+4.00%)	⬆️

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
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0.0% Coverage
0.0% Duplication

[macsux]

Something like this

public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IDiscoveryClient client)
        {
            var eureka = (DiscoveryClient) client;
            eureka.OnApplicationsChange += (sender, applications) =>
            {
                Console.WriteLine("====");
                foreach (var application in applications.GetRegisteredApplications())
                {
                    Console.WriteLine($"App: {application.Name}");
                    foreach (var instance in application.Instances)
                    {
                        Console.WriteLine($"  {instance.Actiontype} {instance.HostName}:{instance.Port}");
                    }
                }
            };

[TimHess]

This implementation should be OK for now, but we'll probably want to revisit with this issue to align with Spring and things like ApplicationEvent

Do you have time to add a unit test for this @macsux?

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Azure Pipelines successfully started running 1 pipeline(s).

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication