What is the test for "manifest necessity" to allow a retrial after a mistrial has been declared?

24 Cf. Arizona v. Washington, 434 U.S. 497, 509, 98 S.Ct. 824, 832, 54 L.Ed.2d 717 (1978) (failure to allow retrial after mistrial declared because of "manifest necessity" would deprive society of its "one complete opportunity to convict those who have violated its laws"; Bozza v. United States, 330 U.S. 160, 166, 67 S.Ct. 645, 649, 91 L.Ed. 818 (1947) (invalid sentence may be corrected even if doing so necessitates increase in punishment because otherwise "no valid and enforceable sentence can be imposed at all" and a convicted criminal will go free).