ORDER_STATE_PENDING 是 {@struct/Order Order} 结构中的 Status 属性的值，表示订单状态为待成交状态。
number
ORDER_STATE_PENDING 的值为 0。
{@var/ORDER_STATE/ORDER_STATE_CLOSED ORDER_STATE_CLOSED}, {@var/ORDER_STATE/ORDER_STATE_CANCELED ORDER_STATE_CANCELED}, {@var/ORDER_STATE/ORDER_STATE_UNKNOWN ORDER_STATE_UNKNOWN}