Why does rclcpp have a make_shared function?

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I can't figure out where it is documented but it seems really odd to me that many of the rclcpp classes use a macro to define a function make_shared that is just an alias for make_shared from the stl. Was the idea here that at some point rclcpp might want to transition to boost::make_shared? The stl make_shared was added to the stl in C++11.

Here is the macro from rclcpp: https://github.com/ros2/rclcpp/blob/f...

There are also the SharedPtr and similar using statements that also seem odd to me. If the intention would be that you could more easily port rclcpp to some system without the stl where are the abstractions for the rest of the stl?