how to achieve one request return multiple response with flask or tornado

This is the pseudo code:

from flask import Flask
app = Flask(__name__)

@app.route('/')
def test():
    result1 = step 1  # This can do something
    return result1
    result2 = step 2  # This can do something 
    return result2

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

step2 must rely on step1, so I think they can not be separated in two request. But because they need some time, so I can not wait for their finish. And I want to know their speed of progress, so I want it to response after every step. How should I do to do it?(There is no database, I can only use cookie.)