dates

we should copy the impl from here https://crates.io/crates/httpdate (or use as a dep, unsure which is better)

Start by reviewing the repository's existing date-handling code, then compare the httpdate crate linked in the issue with the option of copying its implementation. The issue does not name files or tests, and the dependency-versus-copy decision is unresolved; done would require agreeing on that approach and adding the corresponding date support.

Written by the indexing model from the issue text.