-- Test script for property change notification mechanism.-- Note that watching/reading some properties can be very expensive, or-- require the player to synchronously wait on network (when playing-- remote files), so you should in general only watch properties you-- are interested in. local utils = require("mp.utils") local function observe(name)    mp.observe_property(name, "native", function(prop, val)        print("property '" .. prop .. "' changed to '" ..              utils.to_string(val) .. "'")    end)end for _, name in ipairs(mp.get_property_native("property-list")) do    observe(name)end for _, name in ipairs(mp.get_property_native("options")) do    observe("options/" .. name)end