else {
            this.createOptions = createOptions;
        }
        this.impersonationLevel = 0x02; // As seen on NT :~)
        this.securityFlags = (byte) 0x03; // SECURITY_CONTEXT_TRACKING | SECURITY_EFFECTIVE_ONLY
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.internal.smb1.ServerMessageBlock#getResponse()
     */
    @Override

```Python hl_lines="8  10"
{!> ../../docs_src/query_params/tutorial004.py!}
```

////

## Required query parameters

When you declare a default value for non-path parameters (for now, we have only seen query parameters), then it is not required.

If you don't want to add a specific value but just make it optional, set the default as `None`.

### Conventions

Once a new property has been introduced, you need to consider what its conventions will be.

like that curious song about the whiting!'

  `Oh, as to the whiting,' said the Mock Turtle, `they--you've
seen them, of course?'

  `Yes,' said Alice, `I've often seen them at dinn--' she
checked herself hastily.

  `I don't know where Dinn may be,' said the Mock Turtle, `but
if you've seen them so often, of course you know what they're
like.'

  `I believe so,' Alice replied thoughtfully.  `They have their

There is no cancellation propagation for single payload requests.
When the context is canceled, the request will return at once with an appropriate error. 
However, the remote call will not see the cancellation - as can be seen from the 'missing' context on the handler.
The result will be discarded.

### Typed handlers

Typed handlers are handlers that have a specific type for the request and response payloads.

  // processed by the API server eviction subresource handler but has not
  // yet been observed by the PodDisruptionBudget controller.
  // A pod will be in this map from the time when the API server processed the
  // eviction request to the time when the pod is seen by PDB controller
  // as having been marked for deletion (or after a timeout). The key in the map is the name of the pod

And we know that editors can't provide a lot of support (like completion) for `dict`s, because they can't know their keys and value types.

We can do better...

## What makes a dependency

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

FC1C          ; mapped                 ; 0633 062C     # 1.1  ARABIC LIGATURE SEEN WITH JEEM ISOLATED FORM
FC1D          ; mapped                 ; 0633 062D     # 1.1  ARABIC LIGATURE SEEN WITH HAH ISOLATED FORM
FC1E          ; mapped                 ; 0633 062E     # 1.1  ARABIC LIGATURE SEEN WITH KHAH ISOLATED FORM
FC1F          ; mapped                 ; 0633 0645     # 1.1  ARABIC LIGATURE SEEN WITH MEEM ISOLATED FORM

     *       thread
     *   <li>If this field's value == null because of unsafe publication, we know that it isn't the
     *       object associated with our thread, because if it was the publication wouldn't have been
     *       unsafe and we'd have seen our thread as the value. This state is also why a new
     *       ThreadConfinedTaskQueue object must be created for each inline execution, because

# Behind a Proxy

In some situations, you might need to use a **proxy** server like Traefik or Nginx with a configuration that adds an extra path prefix that is not seen by your application.

In these cases you can use `root_path` to configure your application.

The `root_path` is a mechanism provided by the ASGI specification (that FastAPI is built on, through Starlette).

The `root_path` is used to handle these specific cases.