Don't overwrite default serializer settings (#21)

[epbensimpson]

Fixes an issue described in #21 where DefaultRESTClient is setting JsonConvert.DefaultSettings instead of supplying the settings directly to the SerializeObject and DeserializeObject calls.

[TruDan]

@robotdan This would also fix alot of issues we're currently having in our UserApi uSvc. as it cannot deserialize any object with a datetimeoffset that doesn't come from fusionauth, since we don't use unix timestamps anywhere.

Could this be merged? It's a very small change with no effect to the usage of the client library. But with a very big positive impact for anyone using the library. Newtonsoft.Json is the most popular json library for C#. Very widely used.

[mooreds]

We already use Newtonsoft.Json in some of the other parts of this lib. I'm fine with that, but my question is does this require changes to fusionauth-client-builder? I don't believe so, based on this code search: https://github.com/FusionAuth/fusionauth-client-builder/search?q=DefaultRESTClient

[epbensimpson]

I'm not super familiar with how these clients are generated from the templates but I did have a quick look and it didn't seem like DefaultRESTClient was part of that.

[robotdan]

Thanks for the follow up @TruDan and @epbensimpson - we really appreciate your expertise since we (or at least I am) .Net dumb.

If I understand correctly, the serialization settings we are configuring currently are changing the global default configuration for Newtonsoft so it affects any others users of this library in the same runtime?

If that is the case, this would be a great change to make. If you can confirm the above, I am up for merging this PR.

@epbensimpson is correct - this change is only in this repo, the template stuff in the client builder just uses this base rest client code.

For reference, here are the related templates:
https://github.com/FusionAuth/fusionauth-client-builder/blob/master/src/main/client/netcore.client.ftl
https://github.com/FusionAuth/fusionauth-client-builder/blob/master/src/main/client/netcore.client.interface.ftl
https://github.com/FusionAuth/fusionauth-client-builder/blob/master/src/main/client/netcore.client.sync.ftl
https://github.com/FusionAuth/fusionauth-client-builder/blob/master/src/main/client/netcore.domain.ftl

[robotdan]

I'll merge this - if anyone wants to confirm my comments here #27 (comment) that would be great! (just for my own knowledge)

[epbensimpson]

If I understand correctly, the serialization settings we are configuring currently are changing the global default configuration for Newtonsoft so it affects any others users of this library in the same runtime?

Correct - I discovered this issue as we had code that was relying on enums being serialized as the integer value, not as the string representation, and this broke suddenly but I couldn't find anywhere in our code we were adding the StringEnumConverter to the default settings. Eventually I tracked it down to this library based on the IdentityProviderConverter that was being added as well.

[robotdan]

Thanks for the info @epbensimpson much appreciated.