What is the test for deliberate indifference in the context of a deliberate indifference claim?

Several weeks after we decided Brown II , we decided Castro v. County of Los Angeles , 833 F.3d 1060 (9th Cir. 2016) (en banc), cert. denied , U.S. , 137 S.Ct. 831, 197 L.Ed.2d 69 (2017). There, we statedin the prison contextthat, in evaluating due process deliberate indifference claims, we inquire whether "a reasonable officer in the circumstances [would appreciate] the high degree of risk involved." Id. at 1071. That is, we implemented an objective standard.