Close active IMAP sessions during shutdown

src/agents/imap/imapd.c

@@ -4623,6 +4623,15 @@ IMAPServer(void *unused)
         XplConsolePrintf("\rIMAPD: %d server threads outstanding; attempting forceful unload.\r\n", XplSafeRead(Imap.server.active) - 1);
     }
 
+    /*
+     * No listener can publish another accepted connection after this point.
+     * Close the client and Store sockets before waiting for session threads:
+     * an idle client may otherwise leave its worker blocked in ConnRead()
+     * until the normal command timeout expires.  POP3 uses the same shutdown
+     * ordering.
+     */
+    ConnCloseAll();
+
 #if VERBOSE
     XplConsolePrintf("\rIMAPD: Shutting down %d session threads\r\n", XplSafeRead(Imap.session.threads.inUse));
 #endif