async auto-observable value not being updated properly when not bound (only on `v1` branch)

[nadako]

The following code returns Loading on the second value access, unless we bind (and thus wake up and do the triggerAsync thing). Only happens on the v1 branch, master is fine:

import tink.core.Future;
import tink.state.Observable;

function main() {
	var o = Observable.auto(() -> new Future(trigger -> {
		return haxe.Timer.delay(() -> trigger(10), 500).stop;
	}));

	trace(o.value);

	haxe.Timer.delay(() -> {
		trace(o.value); // still Loading
	}, 1000);
}

[back2dos]

That's a "feature": #60

I'm not 100% sure that I like it, but the basic idea is that if the async computation is expensive, then it gets suspended if nobody is interested.

In the above example, nobody is observing any changes. You happen to know that if you wait long enough, the computation should have finished, but that is not quite the rule.

That being said, I'm not very thrilled with the new behavior myself. But I'd be eager to learn more about things that approximate real world use cases, in the hopes of coming up with something that has the intended benefits of #60, without messing up expectations.