A wrapper class around MPI keyvals
MPI::Keyval.create(uniq)
Returns a new MPI::Keyval. If uniq is true, then the attribute associated with a keyval will be deleted from the original communicator to which it was attached when that communicator is duplicated. If uniq is false, then the attribute will simply be copied to the new communicator.
C equivalent: MPI_Keyval_create()