doc: add documentation for blob.bytes() method

doc/api/buffer.md

@@ -513,6 +513,23 @@ added:
 Returns a promise that fulfills with an {ArrayBuffer} containing a copy of
 the `Blob` data.
 
+#### `blob.bytes()`
+
+<!-- YAML
+added:
+  - v20.16.0
+-->
+
+The `blob.bytes()` method returns the byte of the `Blob` object as a `Promise<Uint8Array>`.
+
+```js
+const blob = new Blob(['hello']);
+blob.bytes().then((bytes) => {
+  console.log(bytes); // Outputs: Uint8Array(5) [ 104, 101, 108, 108, 111 ]
+});
+```
+
+
 ### `blob.size`
 
 <!-- YAML
@@ -538,6 +555,8 @@ added:
 Creates and returns a new `Blob` containing a subset of this `Blob` objects
 data. The original `Blob` is not altered.
 
+
+
 ### `blob.stream()`
 
 <!-- YAML