DataTable dynamic update (several times in one function)

[nickkitovsky]

Tell me a way to update fields in the DataTable within one function (this works great if you hang it, for example, on a Button.Pressed handler), but in one function sequentially.

from time import sleep

from textual import on
from textual.app import App, ComposeResult
from textual.coordinate import Coordinate
from textual.widgets import Button, DataTable


class TableApp(App):
    cnt = 0

    def compose(self) -> ComposeResult:
        yield Button()
        yield DataTable(cursor_type='row')

    def on_mount(self) -> None:
        self.table = self.query_one(DataTable)
        self.table.add_column('A')
        self.table.add_row('0')

    def change_value(self):
        self.table.update_cell_at(
            coordinate=Coordinate(row=0, column=0),
            value=self.cnt,
            update_width=True,
        )
        self.cnt += 1

    @on(message_type=Button.Pressed)
    def input_typing_handler(self, event: Button.Pressed) -> None:
        self.change_value()
        sleep(3)  # some hard work
        self.change_value()
app = TableApp()
if __name__ == '__main__':
    app.run()

I don't see two consecutive changes using the change_value function with a break for some external function, I immediately get the last result after the work is done (speed(3) in the example.
I tried to create custom message class and run

self.post_message(MyCustomMessage()) 
sleep(3)  # some hard work
self.post_message(MyCustomMessage())

But the result was the same.
The same applies to different cells; changes are not applied one by one, but only after the function is completely completed