cpp/chrono/time zone/to sys

Converts the std in this time zone to the corresponding std.

@1@ Throws an exception if the conversion is ambiguous or if represents a nonexistent time. @2@ Resolves ambiguity according to the value of : @@ If represents a nonexistent time between two UTC s, those two s will be the same, and that  will be returned.
 * If, returns the earlier.
 * If, returns the later

Return value
The UTC equivalent of according to the rules of this time zone.

Exceptions
@1@ Throws:
 * if the conversion is ambiguous,
 * if represents a nonexistent time.