COPY's take way too long

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DEBUG:client.command: FINISH: Client: 127.0.0.1:47404, IMAP Command '16439.109 UID COPY' took 69.956 seconds

that was copying one message from the inbox to the Archive folder. My initial thought is that getting the locks necessary to read from one folder and write to the other are blocking behind some other locks, but that is still rather long.

Investigation is necessary (which means more debug logging statements)