Adding extended methods to DO State page.

Author: Oxyjun

src/content/docs/durable-objects/api/state.mdx

@@ -5,7 +5,7 @@ sidebar:
   order: 5
 ---
 
-import { Tabs, TabItem, GlossaryTooltip } from "~/components";
+import { Tabs, TabItem, GlossaryTooltip, Type, MetaInfo } from "~/components";
 
 ## Description
 
@@ -267,6 +267,22 @@ export class MyDurableObject extends DurableObject {
 
 - None.
 
+## Extended methods
+
+### `serializeAttachment`
+
+- <code> serializeAttachment(value <Type text="any" />)</code>: <Type text="void" />
+
+  - Keeps a copy of `value` in memory (not on disk) to survive hibernation. The value can be any type supported by the [structured clone algorithm](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm), which is true of most types.
+
+  - If you modify `value` after calling this method, those changes will not be retained unless you call this method again. The serialized size of `value` is limited to 2,048 bytes, otherwise this method will throw an error. If you need larger values to survive hibernation, use the [Storage API](/durable-objects/api/storage-api/) and pass the corresponding key to this method so it can be retrieved later.
+
+### `deserializeAttachment`
+
+- `deserializeAttachment()`: <Type text='any' />
+
+  - Retrieves the most recent value passed to `serializeAttachment()`, or `null` if none exists.
+
 ## Properties
 
 ### `id`