4 * Only accept valid field names in the `field` argument
5 - Ensures the resulting string is a valid HTTP header value
10 * Fix setting empty header from empty `field`
11 * perf: enable strict mode
12 * perf: remove argument reassignments
17 * Accept valid `Vary` header string as `field`
18 * Add `vary.append` for low-level string manipulation
19 * Move to `jshttp` orgainzation
24 * Support array of fields to set