message: global-meshing-heap: check if there is bookkeeping space before meshing
diff: @@ -252,6 +252,9 @@ public:
  void mesh(MiniHeap *dst, MiniHeap *&src) {
  const auto srcSpan = src->getSpanStart();
  + if (dst->meshCount() + src->meshCount() > internal::MaxMeshes)
  + return;
  +
  dst->consume(src);
  const size_t sz = dst->spanSize();
  