Function delete_device 

pub fn delete_device(
    conn: &mut Connection,
    user_id: i64,
    device_id: &str,
    now: &str,
) -> Result<bool>

The manual “log out this device” path (DELETE /devices/{deviceId}, P9): delete the device, cascade its key material and pending to-device rows, and append one [device_list_changes] row for user_id. One transaction. Returns whether a device existed to delete.