message: helper: Implement Comm::GathervVectors in terms of our encapsulation
diff: @@ -68,8 +68,7 @@ void Comm::GathervVectors(const std::vector<T> &in, std::vector<T> &out,
  size_t gatheredSize = 0;
  - int rank;
  - SMPI_Comm_rank(m_MPIComm, &rank);
  + int rank = this->Rank();
  if (rank == rankDestination) // pre-allocate vector
  {
  