assertEquals(10, (int) memoizedSupplier.get());
    // it still should only have executed once due to memoization
    assertEquals(1, countingSupplier.calls);

    Thread.sleep(150);

    assertEquals(20, (int) memoizedSupplier.get());
    // old value expired
    assertEquals(2, countingSupplier.calls);

    assertEquals(20, (int) memoizedSupplier.get());
    // it still should only have executed twice due to memoization

    assertEquals(10, (int) memoizedSupplier.get());
    // it still should only have executed once due to memoization
    assertEquals(1, countingSupplier.calls);

    Thread.sleep(150);

    assertEquals(20, (int) memoizedSupplier.get());
    // old value expired
    assertEquals(2, countingSupplier.calls);

    assertEquals(20, (int) memoizedSupplier.get());
    // it still should only have executed twice due to memoization

### Preprocess the OpenAPI Specification for the Client Generator

The generated code still has some **duplicated information**.

We already know that this method is related to the **items** because that word is in the `ItemsService` (taken from the tag), but we still have the tag name prefixed in the method name too. 😕

We will probably still want to keep it for OpenAPI in general, as that will ensure that the operation IDs are **unique**.

# Security Tools

When you need to declare dependencies with OAuth2 scopes you use `Security()`.

But you still need to define what is the dependable, the callable that you pass as a parameter to `Depends()` or `Security()`.

There are multiple tools that you can use to create those dependables, and they get integrated into OpenAPI so they are shown in the automatic docs UI, they can be used by automatically generated clients and SDKs, etc.

                        log.warn("Disconnected tree while still in use " + this);
                        dumpResource();
                        wasInUse = true;
                        if ( sess.getConfig().isTraceResourceUsage() ) {
                            throw new RuntimeCIFSException("Disconnected tree while still in use");
                        }
                    }

/// tip

The next sections are **not necessarily "advanced"**.

And it's possible that for your use case, the solution is in one of them.

///

## Read the Tutorial first

You could still use most of the features in **FastAPI** with the knowledge from the main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank}.

   * documented as being for use with type parameters that have parametric nullness. But Converter's
   * type parameters do not. Still, we use it here so that we can suppress a warning at a smaller
   * level than the whole method but without performing a runtime null check. That way, we can still
   * pass null inputs to LegacyConverter, and it can violate the contract of Converter.
   *

 *       cancel} on the {@code Future}). So beware: <i>Even if you cancel every preceding {@code
 *       Future} returned by this class, the next task may still have to wait.</i>.
 *   <li>Once an {@code AsyncCallable} returns a {@code Future}, this class considers that task to
 *       be "done" as soon as <i>that</i> {@code Future} completes in any way. Notably, a {@code

{!../../docs_src/response_headers/tutorial002.py!}
```

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

        Thread.sleep(500L)
        println("After delay: " + connectionPool.connectionCount())
      }

      connectionPool.evictAll()
      assertEquals(0, connectionPool.connectionCount()) {
        "Still ${connectionPool.connectionCount()} connections open"
      }
    }
  }

  private fun ensureAllTaskQueuesIdle() {
    val entryTime = System.nanoTime()