Synchronizer problem and TF_OLD_DATA warning

[hnim0110]

When i use your code with my navigation code (use move_base to navigate)with enable odom, the first frame can be saved into map_point but after that this warning appear

Warning: TF_OLD_DATA ignoring data from the past for frame base_link at time 1.71835e+09 according to authority unknown_publisher
Possible reasons are listed at http://wiki.ros.org/tf/Errors%20explained
at line 277 in /tmp/binarydeb/ros-melodic-tf2-0.6.5/src/buffer_core.cpp

and then it seem like cloud_callback is not called cause when i printed out to check the keyframe_queue is empty bit the cout function in cloud_callback that i add to is not called and print m=nothing in terminal.
Thank you for helping me.