cd /cygdrive/z rsync -av /cygdrive/x/supervisor_20191009_111635 .
Another option for Windows 10 users would be the Linux Subsystem from the Microsoft store. If you start the bash from the icon on your desktop you are in a special directoy. Your normal Windows 10 user directory is located at (replace username with your Windows login name):
Unlike the Cygwin implementation you do not see shared or mapped network drives as /mnt/driveletter! So you must use one of the scenarios described below.
Scenario 2: Copy data from a remote server to a local folder