set("b", "b", "b")

    // Create an entry that fails to write to the journal during commit.
    val editor = cache.edit("c")!!
    editor.setString(0, "c")
    editor.setString(1, "c")
    filesystem.setFaultyWrite(journalFile, true)
    editor.commit()

    // Once the journal has a failure, subsequent writes aren't permitted.
    filesystem.setFaultyWrite(journalFile, false)

        grpc -> cfiles [dir=none,label="Fetch Cert",color=purple]

        sds -> SecretManager [label="Generate certificate"]
        SecretManager -> cfiles [label="Write certs to file"]
        cfiles [label="Certificate Files"]
        grpc [shape=diamond]
    }

    subgraph cluster_istiod {
        label = "Istiod"
        color="lightblue"
        ca
    }

	setEventStreamHeaders(w)

	// Listen Publisher and peer-listen-client uses nonblocking send and hence does not wait for slow receivers.
	// Use buffered channel to take care of burst sends or slow w.Write()
	mergeCh := make(chan []byte, globalAPIConfig.getRequestsPoolCapacity()*len(globalEndpoints.Hostnames()))
	localCh := make(chan event.Event, globalAPIConfig.getRequestsPoolCapacity())

It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Add the background task

                    map.put(ExtractData.RESOURCE_NAME_KEY, filename);
                    final String content = extractor.getText(is, map).getContent();
                    writer.write(content);
                    writer.write('\n');
                } catch (final Exception e) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("Exception in an internal extractor.", e);

			Err:  syscall.EISDIR,
		}
	}

	return &LockedFile{f}, nil
}

// TryLockedOpenFile - tries a new write lock, functionality
// it is similar to LockedOpenFile with with syscall.LOCK_EX
// mode but along with syscall.LOCK_NB such that the function
// doesn't wait forever but instead returns if it cannot
// acquire a write lock.
func TryLockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {

 * 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
 */

package jcifs.netbios;


import jcifs.Configuration;

 * 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
 */

package jcifs.smb1.smb1;

class SmbComCreateDirectory extends ServerMessageBlock {

 * 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
 */
package jcifs.util;


import jcifs.Encodable;


/**
 * @author mbechler
 *
 */

// EncodeMsg implements msgp.Encodable
func (z *dataUsageCache) EncodeMsg(en *msgp.Writer) (err error) {
	// map header, size 2
	// write "Info"
	err = en.Append(0x82, 0xa4, 0x49, 0x6e, 0x66, 0x6f)
	if err != nil {
		return
	}
	err = z.Info.EncodeMsg(en)
	if err != nil {
		err = msgp.WrapError(err, "Info")
		return
	}
	// write "Cache"
	err = en.Append(0xa5, 0x43, 0x61, 0x63, 0x68, 0x65)
	if err != nil {