Create a LocalDatetime object having the (default) attribute values.
Declared in <baltzo_localdatetime.h>
LocalDatetime();
` datetimeTz() == bdlt::DatetimeTz() timeZoneId() == "" ` Optionally specify an allocator (e.g., the address of a bslma::Allocator object) to supply memory; otherwise, the default allocator is used.