更新1：
似乎是虚惊一场，但近期应用非常不稳定，可能是因为日子快要到了。
参考：
https://code.google.com/p/goagent/issues/detail?id=20252#c32
https://cloud.google.com/pricing/#app-engine
https://cloud.google.com/pricing/#cloud-stor
原文：
今天收到的邮件，免费的东西总是不能长远的。
GCS cross location copy pricing update
Hello Google Cloud Storage User,
Please be advised that, beginning July 14, 2015, Google will begin charging the following fees for Google Cloud Storage:
$0.01 per GB of data transferred between buckets located in different regions of the same continent
Egress rates per GB of data transferred between buckets located on different continents
Until then, you will be able to view your current usage in the billing details for your project in order to help you estimate the impact of these changes on your monthly spend.
For additional information and examples of this billing charge, please visit https://cloud.google.com/storage/pricing#network-regions
— The Google Cloud Storage Team
Google Inc. 1600 Amphitheatre Parkway, Mountain View, CA 94043
You have received this mandatory service announcement to update you about important changes to Google Cloud Platform or your account.