struct Order
    {
        long id;
        string product;
        double quantity;
    };
    
    struct OrderStatus
    {
        long id;
        boolean accepted;
    };
    
    struct StockEvent
    {
        long id;
        string stock;
        double value;
    };
    
    struct StockFilter
    {
        string stock;
        double minValue;
        double maxValue;
    };
    
    typedef sequence < EventSamples::StockFilter > StockFilters;