HTTP 400 / preconditionFailed should be retried

[ttung]

Environment details

• OS type and version: MacOS 26
• Python version: Python 3.12.11
• pip version: uv
• google-api-python-client version: n/a

Steps to reproduce

Intermittent HTTP 400 / preconditionFailed on Gmail API. A casual web search suggests that other Google APIs also issue preconditionFailed. At least in my use case, retrying with exponential backoff always works. I cannot assert that in all use cases that this is the correct behavior.

Code example

N/A

Stack trace