If you don't know what trio laning is, I made a guide on it a couple of months back. Basically it's where the mid/support/ADC share both the mid and the abyssal dragon wave by roaming back and forth after clearing said waves. This utilizes the gold sharing mechanic in the game and gets the ADC farmed as soon as possible and avoid getting ganked as much as possible as you're always traveling in a group of 3.

Well this is NO LONGER valid with the new June patch since doing so will only guarantee that you miss minions, which leads to loss of gold.

So yeah, ADC players just stay in your lane, farm, and try not to die from ganks especially when the dragon lane is on the top lane. Mid players, you still want to roam but try not to soak too much gold/exp from the dragon lane.

Gold sharing is still a valid concept - you still get more total gold when you gold share so try to do that as much as possible especially in losing situations.

Edit:

You won't be able to find the changes in the official patch notes (they only post the HUGE updates not the hotfixes), but the patch I'm talking about can be found here.