If the specified original contains a value, create an Optional_Base object whose contained value is initialized by moving *original. Otherwise, create a disengaged Optional_Base object. Use the specified allocator to supply memory. original is left in a valid but unspecified state.
Declared in <bslstl_optional.h>
Optional_Base(
std::allocator_arg_t,
allocator_type allocator,
BloombergLP::bslmf::MovableRef<Optional_Base> original);