This is an example of using Temporal.TimeZone for a custom purpose that is not a standard time zone in use somewhere in the world.
NYSETimeZone is a time zone where there are no valid Temporal.PlainDateTime values except when the market is open.
When the market is closed, instants are disambiguated to the opening bell of the next market day.
NOTE: This is a very specialized use of Temporal and is not something you would normally need to do.
{{cookbook/stockExchangeTimeZone.mjs}}