Here is imapsync 1.882 on host petite, a linux system with 0.1/2.0 free GiB of RAM
with Perl 5.22.1 and Mail::IMAPClient 3.39
Transfer started at Sun May  6 01:19:07 2018
PID is 8751
Log file is LOG_imapsync/imapsync_abortme.log ( to change it, use --logfile path ; or use --nolog to turn off logging )
Load is 0.60 0.56 0.79 2/503 on 2 cores
Current directory is /home/gilles/public_html/imapsync
Real user id is gilles (uid 1000)
Effective user id is gilles (euid 1000)
$RCSfile: imapsync,v $ $Revision: 1.882 $ $Date: 2018/05/05 21:10:43 $ 
Command line used:
./imapsync --host1 localhost --user1 tata --passfile1 ../../var/pass/secret.tata --host2 localhost --user2 titi --passfile2 ../../var/pass/secret.titi --pidfile /tmp/imapsync_abortme.pid --logfile imapsync_abortme.log --simulong 4
Temp directory is /tmp ( to change it use --tmpdir dirpath )
kill -QUIT 8751 # special behavior
kill -TERM 8751 # special behavior
kill -INT 8751 # special behavior
kill -USR1 8751 # special behavior
PID file is /tmp/imapsync_abortme.pid ( to change it use --pidfile filepath ; to avoid it use --pidfile "" )
Writing my PID 8751 in /tmp/imapsync_abortme.pid
Are you still here 1/20
Are you still here 2/20
Are you still here 3/20
Are you still here 4/20
Are you still here 5/20
Are you still here 6/20
Are you still here 7/20
Are you still here 8/20
Are you still here 9/20
Are you still here 10/20
Are you still here 11/20
Are you still here 12/20
Are you still here 13/20

Got a signal QUIT (my PID is 8751). Asked to terminate
Here are the final stats of this sync not completely finished so far
Ended by a signal QUIT (my PID is 8751). I am asked to terminate immediately.
You should resynchronize those accounts by running a sync again,
since some messages and entire folders might still be missing on host2.
Exiting with return value 6
Log file is LOG_imapsync/imapsync_abortme.log ( to change it, use --logfile filepath ; or use --nolog to turn off logging )