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 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
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// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package target

import (
	"sync"
	"sync/atomic"

// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package types

/**
 * Marks a method as an event subscriber.
 *
 * <p>The type of event will be indicated by the method's first (and only) parameter, which cannot
 * be primitive. If this annotation is applied to methods with zero parameters, or more than one
 * parameter, the object containing the method will not be able to register for event delivery from
 * the {@link EventBus}.
 *

It's still possible to use `BackgroundTask` alone in FastAPI, but you have to create the object in your code and return a Starlette `Response` including it.

You can see more details in <a href="https://www.starlette.io/background/" class="external-link" target="_blank">Starlette's official docs for Background Tasks</a>.

## Caveat

It requires a little bit more verbose configurations. And as it is based on WSGI (instead of ASGI), it is not designed to take advantage of the high performance provided by tools like Uvicorn, Starlette and Sanic.

The dependency injection system requires pre-registration of the dependencies and the dependencies are solved based on the declared types. So, it's not possible to declare more than one "component" that provides a certain type.

    /**
     * Returns a new immutable array. The builder can continue to be used after this call, to append
     * more values and build again.
     *
     * <p><b>Performance note:</b> the returned array is backed by the same array as the builder, so
     * no data is copied as part of this step, but this may occupy more memory than strictly
     * necessary. To copy the data to a right-sized backing array, use {@code .build().trimmed()}.
     */

You can read more at the end of this page.

///

## `Field` additional arguments

When using `Field()` with Pydantic models, you can also declare additional `examples`:

//// tab | Python 3.10+

```Python hl_lines="2  8-11"