Every open went to the network for the full message, even for a message
the viewer had just shown, and the conversation fetch then downloaded
every member's full body again, the opened one included. The pager's
three panes each started their own detail and thread fetch, so one open
from the Unified Inbox fetched the body twice and the thread twice.
Messages and conversations now live in a shared cache
(`lib/email-detail-cache`), keyed by server, login and JMAP account:
- a held copy renders at once; bodies never change, so it is only
checked, with a keywords/folders-only `Email/get`, when the account's
Email state (from push or our own reads) moved on or the list row the
message was opened from disagrees with it;
- a copy in the offline cache is shown before anything goes out and is
checked the same way;
- a conversation is listed from its members' headers (`Thread/get` and
list properties in one request) and bodies are downloaded only for
the open cards, in one batched `Email/get`;
- concurrent loads of the same message or thread share one request.
The store's network-first `getEmailDetail` is gone; its offline-copy
refresh moved into the cache.
Linus Rath
33e303e248