Return the address of the non‐modifiable cached description of the time zone identified by the specified timeZoneId, and 0 if information for timeZoneId has not previously been cached (by a call to getZoneinfo). If the returned address is non‐zero, the Zoneinfo object returned is guaranteed to be well‐formed (i.e., `ZoneinfoUtil::isWellFormed will return `true' if called with the returned value), and remain valid for the lifetime of this object.