My humble friend and unique engineer Sergey Gruzdov developed this ingenious solution. With his consent, I share this script - it clone files using ReFS block cloning. Volume must be formatted in Server 2016 ReFS and files must reside on same volume.
PS C:\work> .\Clone-FileViaBlockClone.ps1 -InFile "\\sofs\vm\Windows XP SP3-flat.vmdk" -OutFile \\sofs\vm\test.vmdk Clone file using ReFS Block Clone. Cloning '\\sofs\vm\Windows XP SP3-flat.vmdk' to '\\sofs\vm\test.vmdk' Completed in 0.584 second(s)