chrome extension question chrome.scripting.executeScript doesn't wait promise function

as official doc says. chrome.scripting.executeScript can wait the promise result. https://developer.chrome.com/docs/extensions/reference/scripting/#promises

but somehow below code can not wait for the result. I'm using manifest_V3

sample = async () => {
  let prpmise = new Promise((resolve) => setTimeout(resolve, 1000));
  await prpmise;
  return "waited";
}
 
run = async () => {
 let tab = await getCurrentTab();
 let injectionResults = await chrome.scripting.executeScript({
            target: {tabId: tab.id},
            func: sample,
            args: []
        });
 console.log(injectionResults);
 console.log(injectionResults[0].result);
}

I can see console log output as empty object. when I use other function using synchronous return, it returns value, and it works as I expexted.