C182 pilot reported taking evasive action to avoid aircraft crossing through traffic pattern; resulted in a NMAC situation.

Narrative

The other day; another aircraft nearly collided with the one I was flying near ZZZ. I have my private pilot and was working on transitioning to a high powered aircraft; so I was flying with an instructor and we were fulfilling the landing requirements for the endorsement. During one of the climbs; another aircraft nearly collided with mine.The incident occurred right at XA:50 on Day 0. I was climbing on the departure leg of the Runway XX pattern and was nearly ready to make the turn for my crosswind leg. When I looked out the window to make sure the pattern was clear; I saw a low-winged aircraft at nearly the same altitude traveling from northwest to southeast on a course for collision with my aircraft. I immediately dove to avoid the other plane and extended my departure leg to ensure a safe transition back to our normal pattern for the next landing. The instructor I was flying with attempted to reach the other aircraft on the ZZZ frequency as well as the local practice area frequency. We never received a response. Upon landing; we looked at the ADSB website; and found an ADSB track for an RV8 aircraft that nearly intersected with our own at precisely the time we noted the near-collision. Our flight track on flightaware also corroborated the event with a slight drop in altitude and a significant speed increase corresponding to the dive I induced to avoid the traffic.