@Override
    public String toString() {
        return toString(100);
    }
@param position int array of 4 elements
                position[0] and position[1] are discarded
                position[2]-BeforeWindowData or OutputData or AfterWindowData, position[3]- which attribute
@return attribute
modules/siddhi-core/src/main/java/io/siddhi/core/event/stream/StreamEvent.java