## Using `BackgroundTasks` { #using-backgroundtasks }

First, import `BackgroundTasks` and define a parameter in your *path operation function* with a type declaration of `BackgroundTasks`:

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[1,13] *}

**FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.

## Create a task function { #create-a-task-function }

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.sse.internal

internal data class Event(
  val id: String?,
  val type: String?,
  val data: String,

 * href="http://tinyurl.com/ConcurrentHashMap">ConcurrentHashMap.java</a>.
 *
 * @param <K> the type of the keys in the map
 * @param <V> the type of the values in the map
 * @param <E> the type of the {@link InternalEntry} entry implementation used internally
 * @param <S> the type of the {@link Segment} entry implementation used internally
 * @author Bob Lee
 * @author Charles Fry

      "refresh_interval": "1s",
      "number_of_shards": 1,
      "number_of_replicas": 0,
      "auto_expand_replicas": "0-1"
    },
    "analysis": {
      "analyzer": {
        "standard_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "cjk_width",
            "asciifolding",
            "lowercase",
            "stop",
            "stemmer"
          ]
        }

      "refresh_interval": "1s",
      "number_of_shards": 1,
      "number_of_replicas": 0,
      "auto_expand_replicas": "0-1"
    },
    "analysis": {
      "analyzer": {
        "standard_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "cjk_width",
            "asciifolding",
            "lowercase",
            "stop",
            "stemmer"
          ]
        }

  TF_Status* status = TF_NewStatus();
  // Create the variable handle.
  TFE_Op* op = TFE_NewOp(ctx, "VarHandleOp", status);
  if (TF_GetCode(status) != TF_OK) return nullptr;
  TFE_OpSetAttrType(op, "dtype", TF_FLOAT);
  TFE_OpSetAttrShape(op, "shape", {}, 0, status);
  TFE_OpSetAttrString(op, "container", "localhost", 0);
  TFE_OpSetAttrString(op, "shared_name", "", 0);
  if (!device_name.empty()) {

                                    </div>
                                    <div class="form-group row">
                                        <div class="offset-sm-2 col-sm-10">
                                            <button type="submit" class="btn btn-primary" id="submit"
                                                    name="search"
                                                    value="<la:message key="labels.crud_button_search" />">

  </component>
  <component name="ExternalStorageConfigurationManager" enabled="true" />
  <component name="FrameworkDetectionExcludesConfiguration">
    <type id="web" />
  </component>
  <component name="NullableNotNullManager">
    <option name="myDefaultNullable" value="javax.annotation.Nullable" />
    <option name="myDefaultNotNull" value="javax.annotation.Nonnull" />

    val callback: ServerSentEventReader.Callback =
      object : ServerSentEventReader.Callback {
        override fun onEvent(
          id: String?,
          type: String?,
          data: String,
        ) {
          callbacks.add(Event(id, type, data))
        }

        override fun onRetryChange(timeMs: Long) {
          callbacks.add(timeMs)
        }
      }

      clear();
      return Iterables.addAll(this, Iterables.skip(collection, size - maxSize));
    }
    return standardAddAll(collection);
  }

  @Override
  @J2ktIncompatible // Incompatible return type change. Use inherited implementation
  public Object[] toArray() {
    /*
     * If we could, we'd declare the no-arg `Collection.toArray()` to return "Object[] but elements