Construct the first member using the specified value and basicAllocator, with Pair_BslmaIdiomAllocatorArgT placement.
Declared in <bslstl_pair.h>
template<class PARAM>
Pair_First(
PARAM&& value,
BloombergLP::bslma::Allocator* basicAllocator,
Pair_BslmaIdiomAllocatorArgT);