ok    bool
	}{
		{"", 0, 0, "", 0, 0, 0, false, false},
		{"PST8PDT,M3.2.0,M11.1.0", 0, 2159200800, "PDT", -7 * 60 * 60, 2152173600, 2172733200, true, true},
		{"PST8PDT,M3.2.0,M11.1.0", 0, 2152173599, "PST", -8 * 60 * 60, 2145916800, 2152173600, false, true},
		{"PST8PDT,M3.2.0,M11.1.0", 0, 2152173600, "PDT", -7 * 60 * 60, 2152173600, 2172733200, true, true},

	// The format is the TZ environment variable without a colon; see
	// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html.
	// Example string, for America/Los_Angeles: PST8PDT,M3.2.0,M11.1.0
	extend string

	// Most lookups will be for the current time.
	// To avoid the binary search through tx, keep a
	// static one-element cache that gives the correct