* returns a <b>(live) unmodifiable view</b>; see <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#accessor-behavior">the external
 * documentation</a> for details.
 *
 * <p>Examples of use:
 *
 * {@snippet :
 * // Building a mutable value graph
 * MutableValueGraph<String, Double> graph =
 *     ValueGraphBuilder.undirected().allowsSelfLoops(true).build();

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

{* ../../docs_src/background_tasks/tutorial002_an_py310.py hl[13,15,22,25] *}

该示例中，信息会在响应发出 *之后* 被写到 `log.txt` 文件。

如果请求中有查询，它将在后台任务中写入日志。

然后另一个在 *路径操作函数* 生成的后台任务会使用路径参数 `email` 写入一条信息。

## 技术细节 { #technical-details }

`BackgroundTasks` 类直接来自 [`starlette.background`](https://www.starlette.dev/background/)。

它被直接导入/包含到FastAPI以便你可以从 `fastapi` 导入，并避免意外从 `starlette.background` 导入备用的 `BackgroundTask` (后面没有 `s`)。

// 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 cmd

import (
	"bufio"
	"bytes"
	"fmt"

// 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 lifecycle

import (
	"encoding/xml"
	"fmt"

// 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 versioning

import (
	"encoding/xml"
	"strings"

// 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 openid

import (
	"bytes"
	"encoding/base64"

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

    } else {
      Log.i(Tag, message, t)
    }
  }

  /**
   * A trust manager for Android applications that customize the trust manager.
   *
   * This class exploits knowledge of Android implementation details. This class is potentially
   * much faster to initialize than [BasicTrustRootIndex] because it doesn't need to load and
   * index trusted CA certificates.
   */
  internal data class CustomTrustRootIndex(

 *
 *  2. If there is a connection in the pool that can satisfy the request it is used. Note that it is
 *     possible for shared exchanges to make requests to different host names! See
 *     [RealConnection.isEligible] for details.
 *
 *  3. Attempt plans from prior connect attempts for this call. These occur as either follow-ups to
 *     failed connect attempts (such as trying the next [ConnectionSpec]), or as attempts that lost