how to change tooltip text

["Ye Wenbin" <wenbinye@163.com>]

hello, I wrote a elisp which need a feature like x-show-tip.
but I need to change the the text when user is typing.
x-show-tip seems too slow.
I test like this:

(add-hook 'after-change-functions
           (lambda (&rest arg)
             (and (current-word) (x-show-tip (current-word))))
           nil t)

When typing quickly, you can see the tip frame can't follow and
the input character maybe not show in the screen.

Is there a way to reuse the tip frame but change the text? Or is
there other way to implement this feature?

Thanks for advance!

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