# Herbert Wolverson - Hands-on Rust (Highlights)  ## Highlights - When you insert a resource into Legion’s resource handler, it replaces any existing resource of the same type—you don’t need to worry about making duplicates. ([Page 186](zotero://open-pdf/library/items/CFLBUNUV?page=186&annotation=6X7WK8NX)) ^909300028 - Note that flush is called when a system makes changes to the ECS dataset. ([Page 217](zotero://open-pdf/library/items/CFLBUNUV?page=217&annotation=NUCWNYFB)) ^909300029