to
Converts the TimeZone to NSTimeZone.
If the time zone is represented as a fixed number of seconds from UTC+0 (for example, if it is the result of a call to TimeZone.offset) and the offset is not given in even minutes but also includes seconds, this method throws IllegalArgumentException to denote that lossy conversion would happen, as Darwin internally rounds the offsets to the nearest minute.
If the time zone is unknown to the Foundation framework, IllegalArgumentException will be thrown.