* Softnet: an alternative to built-in NAT with better isolation
* Softnet: increase socketpair(2) socket buffer sizes to 1 MiB
* Pass VM's FD and MAC address to the Softnet
* Softnet: implement graceful shutdown
* Bring back the dispatchMain() and task cancellation
* tart pull: check for cancellation when pulling response body
* Don't dispatchMain() in withTaskCancellationHandler()
* Move VNC URL opening logic into VNCWrapper.open()