static Task <AttachmentExecutionResult> RunQuery(string queryString)
    {
        var incomingAttachments = new IncomingAttachments();
        var stream   = BuildStream();
        var metadata = new HeaderDictionary
        {
            { "header1", "headerValue" }
        };

        incomingAttachments.Add("key", new AttachmentStream("key", stream, 3, metadata));
        var services = new ServiceCollection();

        TestServices.AddGraphQlTestTypes(services);

        return(QueryRunner.ExecuteQuery(queryString, services, incomingAttachments));
    }
 public AttachmentContext()
 {
     Outgoing = new OutgoingAttachments();
     Incoming = new IncomingAttachments();
 }