Safest way to send shutdown signal to headless Rock64 SMB server?

[bmurphr1]

Also, if this doesn't work which two pins could I wire with a momentary switch to engage shutdown mode?  I already have the spare switch and I could drill a 1/8" hole, mount the switch to the case, and wire it to the GPIO pins to enable safe shutdown mode to prevent any data corruption or eMMC corruption/loss.  I have a long PDF file about the SBC but it doesn't mention anything of a graceful shutdown method except through scripts and software-initiated shutdowns.  This gives me to plug in power to boot the board and when I'm done just press the button to shut it all down sans-loss/corruption.