The `shutdown` would happen when you are **stopping** the application.

Maybe you need to start a new version, or you just got tired of running it. 🤷

///

### Lifespan function { #lifespan-function }

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

{* ../../docs_src/events/tutorial003_py39.py hl[14:19] *}

     * Wait for the interrupting thread to set DONE. (See interruptTask().) We want to wait so that
     * the interrupting thread doesn't interrupt the _next_ thing to run on this thread.
     *
     * Note: We don't reset the interrupted bit, just wait for it to be set. If this is a thread
     * pool thread, the thread pool will reset it for us. Otherwise, the interrupted bit may have

# character that might be a shell metacharacter, then use eval to reverse
# that process (while maintaining the separation between arguments), and wrap
# the whole thing up as a single "set" statement.
#
# This will of course break if any of these variables contains a newline or
# an unmatched quote.
#

eval "set -- $(

This is something that you have to do yourself in your code, and make sure you use those JSON keys.

It's almost the only thing that you have to remember to do correctly yourself, to be compliant with the specifications.

For the rest, **FastAPI** handles it for you.

///

## Update the dependencies { #update-the-dependencies }

So, to avoid ID collisions, when creating the JWT token for the user, you could prefix the value of the `sub` key, e.g. with `username:`. So, in this example, the value of `sub` could have been: `username:johndoe`.

The important thing to keep in mind is that the `sub` key should have a unique identifier across the entire application, and it should be a string.

## Check it { #check-it }

  private final long totalLoadTime;

  private final long evictionCount;

  /**
   * Constructs a new {@code CacheStats} instance.
   *
   * <p>Five parameters of the same type in a row is a bad thing, but this class is not constructed
   * by end users and is too fine-grained for a builder.
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public CacheStats(
      long hitCount,

  private final long totalLoadTime;

  private final long evictionCount;

  /**
   * Constructs a new {@code CacheStats} instance.
   *
   * <p>Five parameters of the same type in a row is a bad thing, but this class is not constructed
   * by end users and is too fine-grained for a builder.
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public CacheStats(
      long hitCount,

In contrast to a "**container image**" that is the stored static contents, a "**container**" normally refers to the running instance, the thing that is being **executed**.

        }
        sessionBuilder.setProxySelector(proxySelector);

        // Note: we do NOT use WagonTransportConfigurationKeys here as Maven Core does NOT depend on Wagon Transport
        // and this is okay and "good thing".
        DefaultAuthenticationSelector authSelector = new DefaultAuthenticationSelector();
        for (Server server : request.getServers()) {
            AuthenticationBuilder authBuilder = new AuthenticationBuilder();

 *     return myServer;
 *   }
 *
 *   @Override
 *   public void close() throws IOException {
 *     serverSocket.close();
 *   }
 * }
 * }
 *
 * <p id="cleaner">Here is how you might achieve the same thing using {@link java.lang.ref.Cleaner
 * Cleaner}, if you are using a Java version where that is available:
 *
 * {@snippet :
 * public class MyServer implements Closeable {