Try sending a request body: requires to modify generated code to set correct Content-Type.

Author: bkoelman

src/Examples/OpenApiLiblabClientExample/output/csharp/Example/Program.cs

@@ -3,6 +3,7 @@
 using Example;
 using JsonApiDotNetCoreClientExample;
 using JsonApiDotNetCoreClientExample.Config;
+using JsonApiDotNetCoreClientExample.Models;
 using Environment = JsonApiDotNetCoreClientExample.Http.Environment;
 
 var config = new JsonApiDotNetCoreClientExampleConfig
@@ -18,4 +19,9 @@
 // Commented out because it does not work due to broken inheritance.
 //PeopleMessageFormatter.PrintPeople(response);
 
+var postResponse = await client.People.PostPersonAsync(new PersonPostRequestDocument(new PersonDataInPostRequest(PersonResourceType.People)
+{
+    Attributes = new PersonAttributesInPostRequest("Doe", "John")
+}));
+
 Console.WriteLine(response);

src/Examples/OpenApiLiblabClientExample/output/csharp/JsonApiDotNetCoreClientExample/Http/RequestBuilder.cs

@@ -1,5 +1,6 @@
 // This file was generated by liblab | https://liblab.com/
 
+using System.Net.Http.Headers;
 using System.Net.Http.Json;
 using System.Text.Json;
 using JsonApiDotNetCoreClientExample.Http.Serialization;
@@ -112,7 +113,9 @@ public RequestBuilder SetOptionalHeader(string key, object? value, bool explode
     /// </summary>
     public RequestBuilder SetContentAsJson(object content, JsonSerializerOptions? options = null)
     {
-        _content = JsonContent.Create(content, options: options);
+        // HACK: There's no way to set the Content-Type header, which is required for JSON:API.
+        //_content = JsonContent.Create(content, options: options);
+        _content = JsonContent.Create(content, MediaTypeHeaderValue.Parse("application/vnd.api+json"), options);
         return this;
     }