Seg fault issues in snapshotter.cpp

[jihyunl2]

I came across some lines in snapshotter.cpp such as 768 or 826 where smart pointers that haven't been allocated a portion of memory yet were causing segmentation fault.

[jihyunl2]

Line 801: if (future_result == rclcpp::FutureReturnCode::SUCCESS)
doesn't seem to make sense to me. Shouldn't it be != instead? If not, could you explain why? Thanks in advance.