If you were surfing web in US and visiting Europe web sites, then the ISP there may give out the traffic size to the adversaries in US, easier for them to do traffic measuring attack, is that what we TBB users should worry about and how to make them couldn’t correctly measure the traffic?
TBB does nothing to protect against correlation attacks. The network adds padding which could slightly help but the size of that padding is well known.
So the adversaries can detect how many sites you are visiting? And they can tell which internet frame belong to which site (unknown URL or IP address)??