#619 LazyMan

Some APIs let you describe a whole sequence of work in one chained expression and only start doing it once you're done describing. Think of animation builders or test runners: you queue steps, some of them wait, and everything runs in order afterwards.

Build a tiny version of that. LazyMan(name, log) creates a person whose actions are recorded with chained calls and then played back one at a time. Every message is reported through the log callback.

LazyMan("Ada", console.log).eat("toast").sleep(2).eat("soup");
// Hi, I'm Ada.
// Eating toast.
// (2 seconds pass)
// Woke up after 2s.
// Eating soup.

sleepFirst is the impatient exception. No matter where it appears in the chain, its nap happens before anything else, even the greeting:

LazyMan("Ada", console.log).eat("cake").sleepFirst(1);
// (1 second passes)
// Woke up after 1s.
// Hi, I'm Ada.
// Eating cake.

Requirements

• LazyMan(name, log) queues the greeting `Hi, I'm ${name}.` as the first regular step.
• eat(food) queues `Eating ${food}.`.
• sleep(seconds) queues a pause. When the pause is over it logs `Woke up after ${seconds}s.` and only then does the next step run.
• sleepFirst(seconds) works like sleep, but the pause runs before the greeting and every other regular step. Several sleepFirst calls run in the order they were made.
• Every method returns the same object, so calls can be chained.
• Nothing runs synchronously. Playback starts after the current chain of calls has finished, so a sleepFirst at the end of the chain still counts.
• Steps run strictly one after another. Two sleeps add up, they don't overlap.
• Each LazyMan call has its own independent queue.