> grab an esp8266 that I won in a cereal box
> try to make annoying noises come out of it
... it does not work.
> read the docs
... ok, i'm invoking that function properly
> read the source
... but seriously, it's like it doesn't even--
> waaaaaaait a second.
> git blame app/modules/gpio.c -L /serout/ | head
... feature was added 2015-04-03
> power cycle the board
... NodeMCU 0.9.5 build 20150308
> mystery solved.