export class AsyncQueue<T> implements AsyncIterable<T> {  private queue: T[] = []  private resolvers: ((value: T) => void)[] = []   push(item: T) {    const resolve = this.resolvers.shift()    if (resolve) resolve(item)    else this.queue.push(item)  }   async next(): Promise<T> {    if (this.queue.length > 0) return this.queue.shift()!    return new Promise((resolve) => this.resolvers.push(resolve))  }   async *[Symbol.asyncIterator]() {    while (true) yield await this.next()  }} export async function work<T>(concurrency: number, items: T[], fn: (item: T) => Promise<void>) {  const pending = [...items]  await Promise.all(    Array.from({ length: concurrency }, async () => {      while (true) {        const item = pending.pop()        if (item === undefined) return        await fn(item)      }    }),  )}