| An `alias` is a FIDL declaration that assigns a new name to an existing type. |
| This has several benefits: |
| |
| - Using `alias` ensures that there is a single source of truth for the concept |
| the aliased type represents. |
| - It provides a way to name things, especially constrained types. |
| - Disparate uses of the now-aliased type may be linked as being instances of the |
| same concept. |
| |
| It is important to note that aliases do not carry through to the generated |
| bindings code at the moment. In other words, the name assigned to an `alias` |
| declaration will never appear as a declaration name in the generated FIDL code. |
| |
| In this example, adding an `alias` for `Key` allows us to avoid repetition with |
| a bespoke name, while also making clear to the reader that both the `key` value |
| on the `Item` type and the `key` used in the `ReadItem` request struct are |
| purposefully, and not merely coincidentally, the same thing. |
| |
| <<../examples/key_value_store/_callout.md>> |
| <<../examples/key_value_store/_add_read_item_tutorial.md>> |
