HarmonyOS 多线程锁问题

import utils from '@ArkTS.utils'; 
@Sendable 
class A { 
  lock_: utils.locks.AsyncLock = new utils.locks.AsyncLock(); 
  count_: number = 0; 
  async getCount() : Promise<number> { 
    return this.lock_.lockAsync<number>(async () => { 
      return this.count_; 
    }) 
  } 
  async setCount(count: number) { 
    await this.lock_.lockAsync<void>(async () => { 
      this.count_ = count; 
    }) 
  } 
} 
(async () => { 
  let a: A = new A 
  await a.setCount(100) 
  await a.getCount() 
})().then(() => { 
})