Warnings in data generation

[QiuDi233]

Hi! I really appreciate your fantastic work. When I run your code in datagen folder to generate rosbag data, I encountered two warnings. It seems that I didn't mkdir two folders. But I checked the code and config files, I didn't get what to mkdir. I wonder if these warnings necessary. How can I fix it or can I just ignore it? Thank you for your kindest reply.

Warnings are here:
W0410 15:00:56.242570 3319555 adaptive_sampling_benchmark_publisher.cpp:57] Empty benchmark folder string: will not write benchmark files
W0410 15:00:56.242695 3319555 synthetic_optic_flow_publisher.cpp:41] Empty output folder string: will not write synthetic optic flow files