9to5Google managed to enable Fast Share on Android Q with its Google Pixel 3 XL. And from the screenshots shared, they work in a pretty similar way as well – enabling it makes your device visible to others, that can then send files, or even text to you.
The underlying tech that makes Fast Share possible is actually a combination of Bluetooth and WiFi, like iOS’ AirDrop. You can also set a list of devices under “Preferred Visibility” which allows them to send files to you even when you have Fast Share turned off. 9to5Google also states that this is a Google Play Services feature, so it likely won’t be an Android Q exclusive. That said, there is no word as to when the feature will officially launch. (Source: 9to5Google)