Iliza Shlesinger and Josephine Decker know they may not be the most obvious writer-director-star pair, admitting that they are “really different artists.” But they met in the middle for Sundance charmer “Chasing Summer,” which sees the irreverent standup comic in a more dramatic, darkly comic role. “We are really different artists,” she said. “Here’s the truth: At 5 a.m., when you have been having sex for a very long time on set …,” Shlesinger began. “On set, on set,” Wareing emphasized. “… and you are tired, you might need someone else to be like, ‘What if you said this line this way?’” Shlesinger finished.