This week on The Treatment, Elvis welcomes back Emmy-winning actor Bill Hader, who is also the co-creator of the HBO series “Barry,” which has just returned for its third season. Hader also was a cast member on “Saturday Night Live” for eight seasons. Hader tells The Treatment one of the keys to the distinctive tone of “Barry” is taking away the idea of genre. He says the third season deals more directly with the consequences of several of the characters’ actions. And he explains why when writing the show, Barry is often the last character he thinks about.