public string SerializeSubRequest(SubRequest request) { string requestBody = serializer.SerializeObject(request.Body); StringBuilder messagePayload = new StringBuilder() .Append($"POST {request.Url} HTTP/1.1\r\n") .Append($"Content-Length: {requestBody.Length}\r\n") .Append("Content-Type: application/json; charset=UTF-8\r\n"); if (request.Headers != null) { foreach (var header in request.Headers) { messagePayload.Append($"{header.Key}: {header.Value}\r\n"); } } messagePayload.Append("\r\n"); messagePayload.Append(requestBody); return(messagePayload.ToString()); }