in main()
before construction
id: 1, default constructor, payload: 1
after construction
size: 0
capacity: 0
contents:
before push_back()
id: 2, copy constructor from id: 1, payload: 1
after push_back()
size: 1
capacity: 1
contents:
    id: 2, payload: 1
before reserve()
id: 3, copy constructor from id: 2, payload: 1
id: 2, destructor, payload: 1
after reserve()
size: 1
capacity: 2
contents:
    id: 3, payload: 1
exiting main()
id: 3, destructor, payload: 1
id: 1, destructor, payload: 1
Program ended with exit code: 0