The "translate conversations in real-time" part seems to have nothing to do with the Google Pixel Buds - it's already live in the Google Translate app.

In fact, you can try it right now. Open the Google Translate app on android, put on a pair of headphones with a mic, and tap the audio translation. As you hear spoken word in another language, it'll translate in realtime back to your non-google headphones.

*note - The trick is you need to press the button so it enables translation across both languages, as that seems to be the only way to keep translation on even after the first phrase.