A chunk iterator can be used for iterating chunks coordinates of a surface.
The returned type is a ChunkPositionAndArea containing the chunk coordinates and its area.
   for chunk in some_surface.get_chunks() do
     game.player.print("x: " .. chunk.x .. ", y: " .. chunk.y)
     game.player.print("area: " .. serpent.line(chunk.area))
   end| operator ()() → ChunkPositionAndArea |   Get the next chunk position or nil, and increments the iterator. | 
| valid :: boolean [R] | Is this object valid? | 
| object_name :: string [R] | The class name of this object. | 
| help() → string | All methods and properties that this object supports. | 
 Get the next chunk position or nil, and increments the iterator.