Improved handling of optional parameters

[frogcrush]

Is your feature request related to a problem? Please describe.

Some of my API endpoints use optional parameters, eg "includeCancelled" which defaults to true. When refitter generates endpoints, it includes these as required (but nullable) properties, or using the optionalParameters flag sets them to default (which is different than the default specified in the OpenAPI doc).

Describe the solution you'd like
Either set them to the default in the OpenAPI doc (if specified) or add multiple signatures for optional parameters.

Describe alternatives you've considered
Just passing null into optional arguments, as they are then not sent to the server, but this feels messy to me.

Additional context

Take for example the following controller:

[HttpGet("list")]
public async Task<ActionResult<List<ProjectScheduleItemModel>>> GetScheduleForPeriod([Required] DateOnly start, [Required] DateOnly end, [DefaultValue(true)] bool includeCancelled = true)

The following code is generated:

[Headers("Accept: text/plain, application/json, text/json")]
[Get("/api/schedule/list")]
Task<IApiResponse<ICollection<ProjectScheduleItemModel>>> List([Query] System.DateOnly start, [Query] System.DateOnly end, [Query] bool? includeCancelled);

Refitter settings:

{
    "returnIApiResponse": true,
    "optionalParameters": true,
    "codeGeneratorSettings": {
        "dateType": "System.DateOnly",
        "dateTimeType": "System.DateTimeOffset",
        "timeType": "System.TimeOnly",
        "timeSpanType": "System.TimeSpan"
    }
}

Loving the project by the way!

[christianhelle]

@frogcrush Thanks for taking the time to report this. I'm a bit busy with other stuff these days but I'll see what I can do in the next few days

[JeremyBP]

Reading this makes me think that we should improve our #417 Dynamic Querystring Parameters feature so that it would offers a constructor with all requiered parameters and let all other as properties. Or maybe all parameters in constructor with default/null values for optional ones, especially when using records.
Will take a look at it.