queue for async function python telegram.ext

[noctious]

Hi, I have a telegram bot code in which you enter a number, and it counts down from that number to zero.

I need to create a queue to execute the count_to_zero function, so that if another number is recorded during the operation of the function, the bot will send a message that the number has been added to the queue, and the number is in the list, after which it counted the old one, then waited 5 seconds and started counting the new one.
I tried to write using manuals and examples, but I failed because of the asynchrony of the function

import time
from telegram import ForceReply, Update
from telegram.constants import ParseMode
from telegram.ext import Application, CommandHandler, ContextTypes, MessageHandler, filters

async def start(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
    await update.message.reply_html("Send me a number and I'll count from it to zero")

async def echo(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
    msg = update.message.text
    if msg.isdigit():
        msg = int(msg)
        if msg > 0:
            await count_to_zero(msg, update)

async def count_to_zero(num, update):
    for i in range(num, -1, -1):
            await update.message.reply_text(i)
            time.sleep(2)

def main() -> None:
    # Create the Application and pass it your bot's token.
    application = Application.builder().token(TOKEN).build()

    # on different commands - answer in Telegram
    application.add_handler(CommandHandler("start", start))

    # on non command i.e message - echo the message on Telegram
    application.add_handler(MessageHandler(filters.TEXT & ~filters.COMMAND, echo))

    # Run the bot until the user presses Ctrl-C
    application.run_polling()

if __name__ == "__main__":
    main()