Improved defensive programming in IsExpired() methods:
1. Credentials.IsExpired():
- Added explicit check for zero-time expiration (time.Time{})
- Treats uninitialized credentials as expired
- Prevents accidentally treating uninitialized creds as valid
2. SessionInfo.IsExpired():
- Added same explicit zero-time check
- Treats uninitialized sessions as expired
- Protects against bugs where sessions might not be properly initialized
This is important because time.Now().After(time.Time{}) returns true,
but explicitly checking for zero time makes the intent clear and helps
catch initialization bugs during code review and debugging.
Chris Lu
00c37387db