more info and newer builds can be found @ nwgat.ninja

Batch use
mirror from server
bash.exe ./lftp.exe sftp://user:password@site:port -e "set sftp:connect-program './ssh.exe'; mirror --verbose --use-pget-n=8 -c /remote/path /cygdrive/driveletter/folder; quit"
mirror to server
bash.exe ./lftp.exe sftp://user:password@site:port -e "set sftp:connect-program './ssh.exe'; mirror -R --verbose --use-pget-n=8 -c /cygdrive/driveletter/folder /remote/path; quit"