What is the test for a motion to dismiss for prejudicial prearrest delay?

"Prejudice may be shown by '"loss of material witnesses due to lapse of time [citation] or loss of evidence because of fading memories attributable to the delay."' [Citations.]" (People v. Cowan (2010) 50 Cal.4th 401, 430.) "We review for abuse of discretion a trial court's ruling on a motion to dismiss for prejudicial prearrest delay . . . ." (Id. at p. 431.)