995)(purpose of the rules is to encourage plea bargaining, and rules "creat[ e ], in effect, a privilege of the defendant," quoting 2 J. Weinstein & M. Berger, Weinstein's Evidence i)410[05] at 410-43 (1994)); United States v. Barrow, 400 F.3d 109, 116 (2d Cir. 2005)("The underlying purpose of Rule 410 is