| x === y: true | |
| x.baz: 5 | |
| z.has(five): true | |
| z.get(five): 5 | |
| post update 1 -- y.has(three): true | |
| post update 1 -- y.get(three): 3 | |
| post update 1 -- z.has(five): false | |
| post update 2 -- x.has(five): true | |
| post update 2 -- x.get(five): 5 | |
| post update 2 -- x.get(three): 4 |