从Flask下载CSV时，数据未写入CSV

from flask import Flask, make_response
import csv

app = Flask(__name__)

@app.route('/download_csv')
def download_csv():
    # 生成要写入的数据
    data = [
        ['Name', 'Age', 'Country'],
        ['John Doe', '30', 'USA'],
        ['Jane Smith', '25', 'UK'],
        ['Bob Johnson', '35', 'Canada']
    ]

    # 创建 CSV 文件并写入数据
    with open('data.csv', 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerows(data)

    # 构建响应对象
    response = make_response()
    response.headers['Content-Type'] = 'text/csv'
    response.headers['Content-Disposition'] = 'attachment; filename=data.csv'
    response.headers['Cache-Control'] = 'no-cache'

    # 将 CSV 文件内容写入响应对象
    with open('data.csv', 'r') as file:
        response.data = file.read()

    return response

if __name__ == '__main__':
    app.run()