Switching back to a session reads nothing again
Going back to a session you just left, or checking a working session between steps, no longer rescans its whole log. Copying a long chat is faster too.
Bandicot kept a count of each session's waiting messages for only one session at a time, so every switch, and every multiplexer tile, read the session log again. It now remembers sixteen, and a session whose messages were all delivered stops rereading its log at every step.
Side chats and rewinds copy a long chat in one write instead of one per message, the side-chat sweep runs at most every thirty seconds instead of on every list, and starting up reads only the lines that describe runs.
A record written after a cut-off last line now starts on its own line, so it is never lost.