message: Make `min_distance` field optional in DistributedClosestPoint query
  We're currently using the `min_distance` field for debugging and
  should not require users to supply this option.
diff: @@ -390,8 +390,8 @@ public:
  * \note The current implementation assumes that the coordinates and closest_points and contiguous
  * with stride NDIMS. We intend to loosen this restriction in the future
  *
  - * \note We're temporarily also using a min_distance class while debugging this class
  - * and will likely add an option to only use this when a debug flag is presented
  + * \note We're temporarily also using a min_distance field while debugging this class.
  + * The code will use this field if it is present in \a mesh_node.
  */
  void computeClosestPoints(conduit::Node& mesh_node,
  const std::string& coordset) const
  @@ -422,7 +422,11 @@ public:
  xfer_node["cp_index"].set_external(internal::getPointer<axom::IndexType>(mesh_node["fields/cp_index/values"]), npts);
  xfer_node["cp_rank"].set_external(internal::getPointer<axom::IndexType>(mesh_node["fields/cp_rank/values"]), npts);
  xfer_node["closest_point"].set_external(internal::getPointer<double>(mesh_node["fields/closest_point/values/x"]), dim * npts);
  +
  + if(mesh_node.has_path("fields_min_distance"))
  + {
  xfer_node["debug/min_distance"].set_external(internal::getPointer<double>(mesh_node["fields/min_distance/values"]), npts);
  + }
  // clang-format on
  }
  @@ -691,11 +695,15 @@ public:
  : axom::Array<PointType>(closestPts, m_allocatorID);
  // DEBUG
  - auto minDist =
  - ArrayView_from_Node<double>(xfer_node["debug/min_distance"], npts);
  - auto cp_dist = is_first ? axom::Array<double>(npts, npts, m_allocatorID)
  - : axom::Array<double>(minDist, m_allocatorID);
  - ;
  + const bool has_min_distance = xfer_node.has_path("debug/min_distance");
  + auto minDist = has_min_distance
  + ? ArrayView_from_Node<double>(xfer_node["debug/min_distance"], npts)
  + : ArrayView<double>();
  +
  + auto cp_dist = has_min_distance
  + ? (is_first ? axom::Array<double>(npts, npts, m_allocatorID)
  + : axom::Array<double>(minDist, m_allocatorID))
  + : axom::Array<double>(0, 0, m_allocatorID);
  auto query_min_dist = cp_dist.view();
  // END DEBUG
  @@ -777,8 +785,11 @@ public:
  query_pos[idx] = m_points[curr_min.minElem];
  //DEBUG
  + if(has_min_distance)
  + {
  query_min_dist[idx] = sqrt(curr_min.minSqDist);
  }
  + }
  // else
  // {
  // SLIC_INFO(
  @@ -807,10 +818,13 @@ public:
  closestPts.size() * sizeof(PointType));
  // DEBUG
  + if(has_min_distance)
  + {
  axom::copy(minDist.data(),
  query_min_dist.data(),
  minDist.size() * sizeof(double));
  }
  + }
  private:
  RuntimePolicy m_runtimePolicy;
  