We didn't experience the expected performance improvements. Locally under
unit test there was aboout an order of magnitude throughput increase, but
when run against the history benchmark, this new approach was 60% slower.
We're reverting this for now to perform further analysis and better
understand the performance profiling of the python history stack.
Due to pythonnet limitations, the list of SubmitOrderRequest could not be modified by OnMarginCall event handler. We now get a new list from that method and update the list in the wrapper.