Beyond a certain threshold, the sheer volume of messages could push an interface into a separate class of service.

超过某个阈值以后，巨量的消息可以推动接口进入单独的服务分类。

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And it gets worse.By 2020, first-class mail volume is expected to drop by half.

2020年的情况会更糟，一类邮件数量预计将减少一半。

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A member of the Misc package, the volume class controls the volume level on the computer.

Misc包的成员之一Volume类控制着计算机的音量。

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What might be less obvious is that it has been asking for permission to do that since 2009, during which time total mail volume has fallen more than 5% and First-Class volume has drop by more than 12%.

FORBES: First Class Mail is Doomed. Get Over it.

Charges taken in connection to a mandate to prefund retiree health care drove the loss in the latest quarter, but declining first-class and advertising mail volume were a drag on revenue.

WSJ: Postal Service Registers $5.2 Billion Loss

Interestingly, Class C properties are experiencing the largest increase in volume of applicants, as well as the largest effective rent growth.

FORBES: Property Managers Cut Renters Slack But At What Price?