Controller's Post method always has null property values on parameter (ASP.Net Core WebAPI & F#: )

My Controller's Post method always has null property values on parameter when triggered.

Environment:

I'm using ASP.Net Core WebAPI with F#.

Attempt:

I tried to apply a suggestion from this link to my Startup.fs file:

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ContractResolver <-
        Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()

However, GlobalConfiguration is an unrecognized type.

Here's a larger view of my attempt:

type Startup private () =
    new (configuration: IConfiguration) as this =
        Startup() then
        this.Configuration <- configuration

        // *** I INSERTED THIS BELOW *** //
        GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ContractResolver <-
            Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()

Similar questions:

I did review this link. However, nothing worked.

HTTP Post:

This is the Post method where I keep observing null property values on my parameter:

[<HttpPost>]
member x.Post(request:DataTransfer.Request) = (* "request" parameter is always null *)

    request |> Query.carriers  
            |> function
               | Error _     -> x.StatusCode(500) :> IActionResult
               | Ok carriers -> x.Ok(carriers)    :> IActionResult

The actual type is defined here:

[<CLIMutable>]
type Request = { 
    RequestId : string 
    Customer  : Customer
    ItemQtys  : ItemQty seq
}

Client:

My client app makes the following call:

let client   = WebGateway.httpClient APIBaseAddress
let response = client.PostAsJsonAsync("carriers", request) |> toResult

Here's the request type on the client:

[<CLIMutable>]
type Request = { 
    RequestId : string 
    Customer  : Customer
    ItemQtys  : ItemQty seq
}

UPDATE:

I then attempted to apply a suggestion from this link and also using this reference. It didn't work though.

member this.ConfigureServices(services: IServiceCollection) =
    // Add framework services.
    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
            .AddJsonOptions(fun opt -> 

                               let resolver = Newtonsoft.Json.Serialization.DefaultContractResolver()
                               resolver.NamingStrategy <- null
                               opt.SerializerSettings.ContractResolver <- resolver

                           ) |> ignore

Postman:

Screenshots:

Partial Success:

The following seems promising:

Hence, the code above results in actual values sent from the client. However, I haven't found a way to convert the object into the data transfer type that I need.