How to pass value from function to ft.Text (framework FLET)?

I want to create a simple stopwatch in Python using the Flet, how can I get my value out of the while loop?

import flet as ft
from time import sleep

def stopwatch():
    time = 0
    str_time = ''
    while True:
        time += 1
        str_time = str(time)
        print(str_time, time) #for check work or not
        sleep(1)


def main(page: ft.Page):
    t = ft.Text(value=stopwatch(), color='red') #no value is transmitted
    page.controls.append(t)
    page.update()

ft.app(target=main)

I tried to use return and the value 1 was passed, but the while loop stopped there. Possibly I don't know much Python and especially the Flet, but I managed to write such a simple program using TKinter, I want to repeat the same success with Flet)

There is an example of a countdown timer in the flet reference. This is a custom text control. To run it in the background, you use page.run_task() to execute a method that implements the logic. This example has been changed to a stopwatch specification.

import asyncio
import flet as ft

class Stopwatch(ft.Text):
    def __init__(self, seconds):
        super().__init__()
        self.seconds = seconds

    def did_mount(self):
        self.running = True
        self.page.run_task(self.update_timer)

    def will_unmount(self):
        self.running = False

    async def update_timer(self):
        while self.seconds >= 0 and self.running:
            mins, secs = divmod(self.seconds, 60)
            self.value = "{:02d}:{:02d}".format(mins, secs)
            self.update()
            await asyncio.sleep(1)
            self.seconds += 1

def main(page: ft.Page):
    page.add(Stopwatch(0))

ft.app(main)