Class BoundedPubSubPow2Subscription

repos/effect/packages/effect/src/PubSub.ts:1817–1908

      this.unsubscribed ||
      this.self.publisherIndex === this.subscriberIndex ||
      this.self.publisherIndex === this.self.subscribersIndex
    )
  }

  size() {
    if (this.unsubscribed) {
      return 0
    }
    return this.self.publisherIndex - Math.max(this.subscriberIndex, this.self.subscribersIndex)
  }

  poll(): A | MutableList.Empty {
    if (this.unsubscribed) {
      return MutableList.Empty
    }
    this.subscriberIndex = Math.max(this.subscriberIndex, this.self.subscribersIndex)
    if (this.subscriberIndex !== this.self.publisherIndex) {
      const index = this.subscriberIndex & this.self.mask
      const elem = this.self.array[index]!
      this.self.subscribers[index] -= 1
      if (this.self.subscribers[index] === 0) {
        this.self.array[index] = AbsentValue as unknown as A
        this.self.subscribersIndex += 1
      }
      this.subscriberIndex += 1
      return elem
    }
    return MutableList.Empty
  }

  pollUpTo(n: number): Array<A> {
    if (this.unsubscribed) {
      return []
    }
    this.subscriberIndex = Math.max(this.subscriberIndex, this.self.subscribersIndex)
    const size = this.self.publisherIndex - this.subscriberIndex
    const toPoll = Math.min(n, size)
    if (toPoll <= 0) {
      return []
    }
    const builder: Array<A> = []
    const pollUpToIndex = this.subscriberIndex + toPoll
    while (this.subscriberIndex !== pollUpToIndex) {
      const index = this.subscriberIndex & this.self.mask
      const elem = this.self.array[index] as A
      this.self.subscribers[index] -= 1
      if (this.self.subscribers[index] === 0) {
        this.self.array[index] = AbsentValue as unknown as A
        this.self.subscribersIndex += 1
      }
      builder.push(elem)
      this.subscriberIndex += 1
    }
    return builder
  }

  unsubscribe(): void {
    if (!this.unsubscribed) {