What is the test for Fourth Amendment seizure when a police officer approaches an individual and asks them a few questions?

As the United States Supreme Court said in Florida v. Bostick (1991) 501 U.S. 429, 434, 111 S.Ct. 2382, 115 L.Ed.2d 389, "Our cases make it clear that a [Fourth Amendment] seizure does not occur simply because a police officer approaches an individual and asks a few questions. So long as a reasonable person would feel free 'to disregard the police and go about his business,' [citation] the encounter is consensual and no reasonable suspicion is required. The encounter will not trigger Fourth Amendment scrutiny unless it loses its consensual nature.... '... Only when the officer, by means of physical force or show of authority, has in some way restrained the liberty of a [person] may we conclude that a "seizure" has occurred.' " (Ibid.)