gen_race_execute.js

let race=genRace();  // Generator object created.

console.log(race.next()); // @yields {value: "first", done: false} 
console.log(race.next()); // @yields {value: "second", done: false}
console.log(race.next()); // @yields {value: "third", done: false}
console.log(race.next()); // @returns {value: "stupid race", done: true}
console.log(race.next()); // @returns {value: undefined, done: true}