TestPoolItem ctor 1, dtor 0, count 1
Items in use: 1
TestPoolItem ctor 2, dtor 0, count 2
Items in use: 2
TestPoolItem ctor 2, dtor 0, count 2
Items in use: 1
TestPoolItem ctor 2, dtor 0, count 2
Items in use: 2
TestPoolItem ctor 3, dtor 0, count 3
Items in use: 3
TestPoolItem ctor 4, dtor 0, count 4
Items in use: 4
TestPoolItem ctor 4, dtor 0, count 4
Items in use: 3
TestPoolItem ctor 4, dtor 0, count 4
Items in use: 2
TestPoolItem ctor 4, dtor 1, count 3
Items in use: 1
TestPoolItem ctor 4, dtor 2, count 2
Items in use: 0
