When processing the Expires header in HttpHeaderParser, and when the value is invalid it logs an error.

https://github.com/google/volley/blob/master/src/main/java/com/android/volley/toolbox/HttpHeaderParser.java#L138

However, Cloudflare often sets this field to 0 or -1, causing the log to be spammed with warnings. I'd rather see the warning not being logged at all, of a simple filter for 0 and -1.