Generated C# Configuration should allow setter for the ApiClient

Description

The configuration object that is generated for csharp code only contains a getter for the ApiClient. I want to be able to set the my own ApiClient because I am using other code I have written that generates a RestClient and handles various authentication scenarios that I need to cover.

Suggest a fix/enhancement

I was able to get the generated code to work they way I wanted by modifying the generated Configuration.cs file to add a setter for ApiClient like this

    private ApiClient _apiClient = null;
    /// <summary>
    /// Gets an instance of an ApiClient for this configuration
    /// </summary>
    public virtual ApiClient ApiClient
    {
        get
        {
            if (_apiClient == null) _apiClient = CreateApiClient();
            return _apiClient;
        }
		set { _apiClient = value; } //<-- *****I added this ****
    }

I am then using the code like this

//Creating the corporations api
CorporationsApi _corpApi = new CorporationsApi();

//Setting up the configuration with correct authentication
//Creating the api client and passing it a session
ApiClient corpApiClient = new ApiClient(GetParameters.getUri());
corpApiClient.RestClient = Client.createSession(); //<--***this method is where I use my own
//code to create an authenticated RestClient ****
//Creating a configuration and passing it the api client and setting the base path
Configuration corpApiConfig = new Configuration();
corpApiConfig.BasePath = GetParameters.getUri();
corpApiConfig.ApiClient = corpApiClient; //<--***here I am using the setter I made ****
//Giving the configuration object to our instance of the corporation api
_corpApi.Configuration = corpApiConfig;

Start by locating the C# template or generator entry point that produces Configuration.cs, then compare it with the setter shown in the issue. Generate a C# client and verify that the resulting Configuration.ApiClient can be assigned to a caller-provided ApiClient.