WriteResponseAsync virtual (#736)

Author: sungam3r

src/Transports.AspNetCore/GraphQLHttpMiddleware.cs

@@ -246,7 +246,7 @@ protected virtual Task WriteErrorResponseAsync(HttpContext context, string error
             return _serializer.WriteAsync(context.Response.Body, result, GetCancellationToken(context));
         }
 
-        private Task WriteResponseAsync<TResult>(HttpResponse httpResponse, IGraphQLSerializer serializer, CancellationToken cancellationToken, TResult result)
+        protected virtual Task WriteResponseAsync<TResult>(HttpResponse httpResponse, IGraphQLSerializer serializer, CancellationToken cancellationToken, TResult result)
         {
             httpResponse.ContentType = "application/json";
             httpResponse.StatusCode = 200; // OK

tests/ApiApprovalTests/GraphQL.Server.Transports.AspNetCore.approved.txt

@@ -36,6 +36,7 @@ namespace GraphQL.Server.Transports.AspNetCore
         protected virtual System.Threading.Tasks.Task RequestExecutedAsync(in GraphQL.Server.Transports.AspNetCore.GraphQLRequestExecutionResult requestExecutionResult) { }
         protected virtual System.Threading.Tasks.Task RequestExecutingAsync(GraphQL.Transport.GraphQLRequest request, int? indexInBatch = default) { }
         protected virtual System.Threading.Tasks.Task WriteErrorResponseAsync(Microsoft.AspNetCore.Http.HttpContext context, string errorMessage, System.Net.HttpStatusCode httpStatusCode) { }
+        protected virtual System.Threading.Tasks.Task WriteResponseAsync<TResult>(Microsoft.AspNetCore.Http.HttpResponse httpResponse, GraphQL.IGraphQLSerializer serializer, System.Threading.CancellationToken cancellationToken, TResult result) { }
     }
     public readonly struct GraphQLRequestExecutionResult
     {