message: helper: Implement Comm::AllGatherArrays in terms of our encapsulation
diff: #include "adios2/common/ADIOSMPI.h"
  -#include <stdexcept> //std::runtime_error
  -
  namespace adios2
  {
  namespace helper
  @@ -89,16 +87,7 @@ template <>
  void Comm::AllGatherArrays(const size_t *source, const size_t sourceCount,
  size_t *destination) const
  {
  - int countsInt = static_cast<int>(sourceCount);
  - int result = MPI_Allgather(const_cast<size_t *>(source), countsInt,
  - ADIOS2_MPI_SIZE_T, destination, countsInt,
  - ADIOS2_MPI_SIZE_T, m_MPIComm);
  -
  - if (result != MPI_SUCCESS)
  - {
  - throw std::runtime_error("ERROR: in ADIOS2 detected failure in MPI "
  - "Allgather type size_t function\n");
  - }
  + this->Allgather(source, sourceCount, destination, sourceCount);
  }
  // ReduceValues full specializations forward-declared in 'adiosComm.inl'.
  