Demonstration of `@effection/subscription` bug wherein subscribables stored as instance properties don't work

eager-property-subscribable.ts

import { EventEmitter } from "events";
import { Operation } from "effection";
import { on } from '@effection/events';
import { Subscribable } from '@effection/subscription';

export class Atom<S> {
  subscriptions = new EventEmitter();

  // get states() {
  //   return Subscribable.from(on(this.subscriptions, 'state'))
  //     .map(([state]) => state as S)
  // }
  states = Subscribable.from(on(this.subscriptions, 'state'))
    .map(([state]) => state as S);

  constructor(public state: S) {}

  update(fn: (state: S) => S) {
    this.state = fn(this.state);
    this.subscriptions.emit("state", this.state);
  }

  once(predicate: (state: S) => boolean): Operation<S | undefined> {
    return this.states.filter(predicate).first();
  }
}

import { spawn, timeout } from 'effection';

import { main } from '@effection/node'; //

main(function*(): Operation<void> {
  let atom = new Atom(0);

  yield spawn(function*(): Operation<void> {
    while (true) {
      yield timeout(1000);
      atom.update(count => count + 1)
    }
  });
  yield spawn(function*(): Operation<void> {
    yield atom.states.forEach(function*(count) {
      console.log('count is', count);
    })
  })

  yield atom.once(count => count >= 5);
});