Does beating that occurs within the context of an arrest or detention constitute persecution?

("We have never held that a beating that occurs within the context of an arrest or detention constitutes persecution per se. Rather, we have held that . . . the agency must be 'keenly sensitive' to context in evaluating whether the harm suffered rises to the level of persecution." (quoting Beskovic v. Gonzales, 467 F.3d 223, 226 (2d Cir. 2006)))). We discern no error in this determination, and so conclude that the BIA acted reasonably in deciding that the harm Ai-Yun suffered did not constitute past persecution and therefore could not support her asylum application.