Packer-Cn/website/source/partials/common/bootcommand/_VNCConfig.html.md

The boot command "typed" character for character over a VNC connection to the machine, simulating a human actually typing the keyboard.

Keystrokes are typed as separate key up/down events over VNC with a default 100ms delay. The delay alleviates issues with latency and CPU contention. You can tune this delay on a per-builder basis by specifying "boot_key_interval" in your Packer template, example:

   "builders": [
        {
           "type": "...",
           "boot_key_interval": "10ms"
           ...
        }
  ]