{
	const s = stream(1);
	const initialValue = s();
	s(2);
	const newValue = s();
	console.assert(initialValue === 1);
	console.assert(newValue === 2);
}

{
	const s = stream();
	console.assert(s() === undefined);
}

{
	const s: Stream<number | undefined> = stream(1);
	s(undefined);
	console.assert(s() === undefined);
}

{
	const s = stream(stream(1));
	console.assert(s()() === 1);
}

{
	const s = stream();
	const doubled = stream.combine(s => s() * 2, [s]);
	s(2);
	console.assert(doubled() === 4);
}

 toJSON() {
   return {
     name: this.name(),
     type: RoleType[this.type()],
     attributes: this.attributes.toJSON()
   };
 }

 toJSON() {
   return {
     id: this.id(),
     plugin_id: this.pluginId(),
     properties: this.properties.toJSON()
   };
 }