private class Itr implements Iterator<E> {
    /** Index of element to be returned by next, or a negative number if no such. */
    private int nextIndex;

    /**
     * nextItem holds on to item fields because once we claim that an element exists in hasNext(),
     * we must return it in the following next() call even if it was in the process of being removed
     * when hasNext() was called.
     */

  // it doesn't escape this class
  @SuppressWarnings("Immutable")
  private final int[] array;

  /*
   * TODO(kevinb): evaluate the trade-offs of going bimorphic to save these two fields from most
   * instances. Note that the instances that would get smaller are the right set to care about
   * optimizing, because the rest have the option of calling `trimmed`.
   */

// ways of matching an originator; by user, group, or service account.
// +union
message Subject {
  // `kind` indicates which one of the other fields is non-empty.
  // Required
  // +unionDiscriminator
  optional string kind = 1;

  // `user` matches based on username.
  // +optional
  optional UserSubject user = 2;

	QueueLimit uint64          `json:"queueLimit"`
	Transport  *http.Transport `json:"-"`
	Username   string          `json:"username"`
	Password   string          `json:"password"`
}

// Validate ElasticsearchArgs fields
func (a ElasticsearchArgs) Validate() error {
	if !a.Enable {
		return nil
	}
	if a.URL.IsEmpty() {
		return errors.New("empty URL")
	}
	if a.Format != "" {
		f := strings.ToLower(a.Format)

        }
    }

    @Test
    public void searchTestWithLabel() throws Exception {
        Map<String, String> params = new HashMap<>();
        params.put("fields.label", TEST_LABEL);
        params.put("num", "100");
        String response = checkMethodBase(new HashMap<>()).params(params).get("/api/v1/documents").asString();

							key="labels.index_label"
						/></label>
					<div class="col-lg-5 col-md-8 col-sm-7 col-xs-6">
						<la:select property="fields.label" styleId="labelTypeSearchOption" multiple="true" styleClass="form-control">
							<c:forEach var="item" items="${labelTypeItems}">
								<la:option value="${f:u(item.value)}">${f:h(item.label)}</la:option>

   END OF TERMS AND CONDITIONS

   APPENDIX: How to apply the Apache License to your work.

      To apply the Apache License to your work, attach the following
      boilerplate notice, with the fields enclosed by brackets "[]"
      replaced with your own identifying information. (Don't include
      the brackets!)  The text should be enclosed in the appropriate
      comment syntax for the file format. We also recommend that a

   END OF TERMS AND CONDITIONS

   APPENDIX: How to apply the Apache License to your work.

      To apply the Apache License to your work, attach the following
      boilerplate notice, with the fields enclosed by brackets "[]"
      replaced with your own identifying information. (Don't include
      the brackets!)  The text should be enclosed in the appropriate
      comment syntax for the file format. We also recommend that a

```

/// tip

Pydantic 是 FastAPI 中所有数据验证和序列化的核心，当你在没有设默认值的情况下使用 `Optional` 或 `Union[Something, None]` 时，它具有特殊行为，你可以在 Pydantic 文档中阅读有关<a href="https://docs.pydantic.dev/latest/concepts/models/#required-optional-fields" class="external-link" target="_blank">必需可选字段</a>的更多信息。

///

### 使用Pydantic中的`Required`代替省略号(`...`)

如果你觉得使用 `...` 不舒服，你也可以从 Pydantic 导入并使用 `Required`：

```Python hl_lines="2  8"

			} else {
				// Iterating over the partInfos and asserting the fields.
				for j, actualMetaData := range actualResult.Parts {
					//  Asserting the PartNumber in the PartInfo.
					if actualMetaData.PartNumber != expectedResult.Parts[j].PartNumber {