Support for EnumMemberAttribute in JsonConverterEnum

[kolkinn]

Hi, I wonder if supporting EnumMemberAttribute in JsonConverterEnum is planned and if so what the ETA is?

Json.NET supports EnumMemberAttribute to customize enum name values. It is a well used feature.

You don't need it in 3.0, but you will get a lot of requests for customizing enum names. Design for adding it in the future.

Originally posted by @JamesNK in dotnet/corefx#38702 (comment)

[ericstj]

/cc @steveharter

We should discuss if we want to support this and other attributes from System.Runtime.Serialization before adding them.

[ericstj]

The basic scenario here is to provide control of the value names used for enum serialization. DCS and Json.NET use EnumMemberAttribute, XML uses XmlEnumAttribute.

[CodeBlanch]

For anyone blocked by this, here's a NuGet package with a converter (JsonStringEnumMemberConverter) we can use ahead of the 5.0 drop: Macross.Json.Extensions

Supports nullable enum types and adds EnumMemberAttribute support.

[layomia]

From @AraHaan in #36931:

I personally think that EnumMember should be supported, many users try to use it with the JsonStringEnumConverter that comes shipped with System.Text.Json itself. Because of this they can run into an System.Text.Json.JsonException from doing such which sucks.

Take a look at the draft pr that is on hold because this is 1 of the issues they face when trying to eradicate newtonsoft.json: RehanSaeed/Schema.NET#100

Also take a look at a version of my code which did that, then I have to now struggle trying to get my stuff to compile because now I got to create a string extension method that could allow null strings somehow and then filter it to the enum values accordingly manually which also sucks.
https://paste.mod.gg/giwezarimo.cs
https://paste.mod.gg/nuqofuwamu.cs
https://paste.mod.gg/gunoqemufu.cs

You can literally use this code as a minimal example and as you can tell my code will not compile as this stuff is lacking. Note: I only made this change because of that pull request above I seen that it used EnumMember and that it used a converter I did not really know about so I thought "Wait a second so my manual converters is not needed at all?"