How can geometry_msgs::Point use push_back()?

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Hello, guys.

I'm trying to study rviz with tutorials provided by ros wiki. I built a sample of document using catkin_make, saw the result.

On the line of this sample codes,

...
visualization_msgs::Marker points, line_strip, line_list;
...
for(ellipsis) {
    ...
    geometry_msgs::Point p;
    p.x = (int32_t)i - 50;
    p.y = y;
    p.z = z;

    points.points.push_back(p);
    ...
}
...

How can the variable of geometry_msgs::Point type use push_back()?

I saw it's msg header on the link
It is just msg consist of 3 variables of float64 type. The function, push_back(), It appears to be used like push_back of stl.

Could you tell me how this works?