Allow for a custom/wrapped HttpClient class

[mvandevy]

I'd like to have the possibility to specify which HttpClient to use. Although the System.Net.Http.HttpClient doesn't really implement an interface, I still want to be able to specify another type which completely respects the method signatures currently found on the System.Net.Http.HttpClient. The type I would specify would be a wrapper around the current System.Net.Http.HttpClient.

Why would I need this? I'm currently in need to wrap the HttpClient calls in order to make my client more robust. With this I mean that when a call to a service fails, due to timeouts, or network errors, ... I'd likt to retry the call a number of times, or with an exponential backoff mechanism. For this I would currenlty use the Polly library which allows me to do just that. However, today I need to wrap the calls the client calls, while it would be really helpful to have this functionality by being able to inject the HttpClient type.

If desired I can even create a pull request as I already have the code changes.

[RicoSuter]

I'd say we add a setting SwaggerToCSharpClientGeneratorSettings.HttpClientType (default "System.Net.Http.HttpClient") and replace all "System.Net.Http.HttpClient" with this setting...

What do you think?

[mvandevy]

Seems to be just like the approach we took. Except for the naming, but HttpClientType would certainly cut it.

[RicoSuter]

Yes, the naming is like DateTimeType which already exists... Can you create a PR with only these changes?

[mvandevy]

I've prepared a pull request, but I've got a couple of issues due to only having VS2017 at my disposal. I'm not able to check in the NSwagStudio because VS2017 restructured it & I can't open the NSwag.Core.sln because VS2017 will automatically try to convert the .xproj files to the new .csproj files. Do you have any objection to these conversion? If you do, I can push an isolated pull request without touching the abovementioned projects.

[RicoSuter]

I'll do this upgrade myself and remove the NSwag.Core.sln solution completely if this is possible... Just create a PR for the new setting

[RicoSuter]

#666