What is the test under the Fourth Amendment of search and seizure?

16 As was said by Chief Justice Warren, speaking for the court in Terry v. Ohio, supra, 392 U.S. 1, 19--20, 88 S.Ct. 1868, 1879, 20 L.Ed.2d 889: '(T)he central inquiry under the Fourth Amendment (is) the reasonableness in all the circumstances of the particular governmental invasion of a citizen's personal security. 'Search' and 'seizure' are not talismans. . . . ( ) . . . (When) we deal . . . with an entire rubric of police conduct--necessarily swift action predicated upon the on-the-spot observations of the officer on the best--which historically has not been, and as a practical matter could not be, subjected to the warrant procedure . . . the conduct involved . . . must be tested by the Fourth Amendment's general proscription against unreasonable searches and seizures.'