assertEquals(written, counter.getCount());

    byte[] data = new byte[10];
    counter.write(data);
    written += 10;
    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    counter.write(data, 0, 5);
    written += 5;
    assertEquals(written, out.size());
    assertEquals(written, counter.getCount());

    counter.write(data, 2, 5);
    written += 5;

如果你查看 `/docs`，會看到欄位 `data` 需要 base64 編碼的位元組：

<div class="screenshot">
<img src="/img/tutorial/json-base64-bytes/image01.png">
</div>

你可以發送如下的請求：

```json
{
    "description": "Some data",
    "data": "aGVsbG8="
}
```

/// tip

`aGVsbG8=` 是 `hello` 的 base64 編碼。

///

接著 Pydantic 會將該 base64 字串解碼，並在模型的 `data` 欄位中提供原始位元組。

你會收到類似以下的回應：

```json
{

 * This factory maintains a registry of data store implementations and provides methods
 * to register, retrieve, and discover available data stores.
 *
 * <p>Data stores are registered by name and class name, allowing flexible lookup.
 * The factory also supports dynamic discovery of data store plugins by scanning
 * JAR files for data store configurations.</p>
 *

            searchPaging(data, form);
        });
    }

    /**
     * Sets up search paging data for rendering the request header list.
     *
     * @param data the render data to populate
     * @param form the search form containing current search criteria
     */
    protected void searchPaging(final RenderData data, final SearchForm form) {

            searchPaging(data, form);
        });
    }

    /**
     * Sets up data for search result pagination.
     *
     * @param data the render data
     * @param form the search form
     */
    protected void searchPaging(final RenderData data, final SearchForm form) {
        RenderDataUtil.register(data, "fileAuthenticationItems",

          export VAULT_TOKEN
          export data=$(vault read -format=json aws-test/creds/elasticsearch-ci-s3)
          export amazon_s3_access_key=$(echo $data | jq -r .data.access_key)
          export amazon_s3_secret_key=$(echo $data | jq -r .data.secret_key)
          unset VAULT_TOKEN data
          set -x

* Read the body of the request as JSON.
* Convert the corresponding types (if needed).
* Validate the data.
    * If the data is invalid, it will return a nice and clear error, indicating exactly where and what was the incorrect data.
* Give you the received data in the parameter `item`.

		success    bool
	}{
		// Invalid inputs.
		{
			[]string{"data{1...17}/export{1...52}"},
			[]uint64{14144},
			nil,
			false,
		},
		// Valid inputs.
		{
			[]string{"data{1...3}"},
			[]uint64{3},
			[][]uint64{{3}},
			true,
		},
		{
			[]string{"data/controller1/export{1...2}, data/controller2/export{1...4}, data/controller3/export{1...8}"},
			[]uint64{2, 4, 8},

	"http://127.0.0.1:9004/tmp/multisiteb/data/disterasure/xl{5...8}" >/tmp/siteb_1.log 2>&1 &
minio server --address 127.0.0.1:9004 "http://127.0.0.1:9003/tmp/multisiteb/data/disterasure/xl{1...4}" \
	"http://127.0.0.1:9004/tmp/multisiteb/data/disterasure/xl{5...8}" >/tmp/siteb_2.log 2>&1 &

minio server --address 127.0.0.1:9005 "http://127.0.0.1:9005/tmp/multisitec/data/disterasure/xl{1...4}" \

@app.get("/events", response_class=EventSourceResponse)
async def stream_events() -> AsyncIterable[ServerSentEvent]:
    yield ServerSentEvent(data={"status": "started"}, event="status", id="1")
    yield ServerSentEvent(data={"progress": 50}, event="progress", id="2")
```

Use `raw_data` instead of `data` to send pre-formatted strings without JSON encoding:

```python
yield ServerSentEvent(raw_data="plain text line", event="log")
```