I can tell when jet lag is starting to bite because I make more typos. What I really need is a wearable caffeine delivery device that supports remote control. That way I could instrument my spellchecker and set a threshold for automated delivery of a jolt of caffeine.
Next order of business is to figure out how to do real-time lexical analysis of human speech and trigger the caffeine jolt when I stop making sense. "Hey Siri, light me up!"
The challenge will be to remember to take the device off before going to the bar, or risk a potentially life-threatening caffeine overdose some time after midnight when you are busy solving all the world's problems…
Incidentally, my recommended method of jet lag mitigation involves self-medication with melatonin and gin & tonic; repeat as needed until symptoms pass or no longer seem important.