diff --git a/vtkm/filter/flow/internal/Messenger.cxx b/vtkm/filter/flow/internal/Messenger.cxx
index 52c582f201..dff804cc8a 100644
--- a/vtkm/filter/flow/internal/Messenger.cxx
+++ b/vtkm/filter/flow/internal/Messenger.cxx
@@ -277,7 +277,7 @@ void Messenger::SendDataSync(int dst, int tag, vtkmdiy::MemoryBuffer& buff)
   if (it == this->SyncSendBuffers.end())
   {
     std::vector<std::pair<int, vtkmdiy::MemoryBuffer>> vec;
-    vec.push_back(std::move(entry));
+    vec.emplace_back(std::move(entry));
     this->SyncSendBuffers.insert(std::make_pair(tag, std::move(vec)));
   }
   else
diff --git a/vtkm/filter/flow/internal/Messenger.h b/vtkm/filter/flow/internal/Messenger.h
index 42d554ae51..b6a0acb40b 100644
--- a/vtkm/filter/flow/internal/Messenger.h
+++ b/vtkm/filter/flow/internal/Messenger.h
@@ -44,6 +44,11 @@ public:
 #endif
   }
 
+  Messenger(const Messenger&)            =delete;
+  Messenger(Messenger&&)                 =default;
+  Messenger& operator=(Messenger&&)      =default;
+  Messenger& operator=(const Messenger&) =delete;
+
   int GetRank() const { return this->Rank; }
   int GetNumRanks() const { return this->NumRanks; }
 
@@ -108,7 +113,7 @@ private:
 
   //Member data
   // <tag, {dst, buffer}>
-  std::map<int, std::vector<std::pair<int, vtkmdiy::MemoryBuffer>>> SyncSendBuffers;
+  std::map<int, std::vector<std::pair<int, vtkmdiy::MemoryBuffer>>> SyncSendBuffers = {};
   std::map<int, std::pair<std::size_t, std::size_t>> MessageTagInfo;
   MPI_Comm MPIComm;
   std::size_t MsgID;