[PATCH] net/imap: dedupe attr keys in Net::IMAP::FetchData
Since attr hash keys are frequently reused, it makes sense to
deduplicate them up front.
This saves one allocation per-attr, per-message. When running
imap.fetch(1..-1, 'UID') on a mailbox with 30000 messages;
this saves 30000 allocations.
This relies on the String#-@ change in [Feature #13077]
- net/imap: use frozen, deduplicated string in attr name (key)
Trivial (1-byte change :), I may commit in a few days if no response.