```sh
var = map_size handle
```
Returns the map size based on the provided map handle.
The map handle.
The map size.
```sh
handle = map
result = map_put ${handle} a 1
result = map_put ${handle} b 2
result = map_put ${handle} c 3
result = map_size ${handle}
assert_eq ${result} 3
release ${handle}
```