code: @WithBridgeMethods(value = PostgreSQLQuery.class, castRequired = true)
      public C distinctOn(Expression<?>... exprs) {
          return addFlag(Position.AFTER_SELECT,
              Expressions.template(Object.class, "distinct on({0}) ",
              ExpressionUtils.list(Object.class, exprs)));
      }
docs: adds a DISTINCT ON clause
  
  @param exprs
  @return