当我点击react中的submit按钮时，如何在5秒内显示加载指示器？

state = {
  loading: false
};

handleSubmit = () => {
  this.setState({ loading: true });

  setTimeout(() => {
    this.setState({ loading: false });
  }, 5000);
};

render() {
  const { loading } = this.state;

  return (
    <div>
      {loading && <div className="loading-indicator">加载中...</div>}
      <button onClick={this.handleSubmit}>提交</button>
    </div>
  );
}

.loading-indicator {
  display: inline-block;
  padding: 5px;
  background-color: #f1f1f1;
  border: 1px solid #ccc;
}