* Response and normal event sequences will not be received.
   *
   * This event will only be received when a Cache is configured for the client.
   */
  open fun cacheHit(
    call: Call,
    response: Response,
  ) {
  }

  /**
   * Invoked when a response will be served from the network. The Response will be
   * available from normal event sequences.
   *

///

The files will be uploaded as "form data".

If you declare the type of your *path operation function* parameter as `bytes`, **FastAPI** will read the file for you and you will receive the contents as `bytes`.

Keep in mind that this means that the whole contents will be stored in memory. This will work well for small files.

### Server Memory { #server-memory }

For example, if your code loads a Machine Learning model with **1 GB in size**, when you run one process with your API, it will consume at least 1 GB of RAM. And if you start **4 processes** (4 workers), each will consume 1 GB of RAM. So in total, your API will consume **4 GB of RAM**.

---> 100%
```

</div>

That will download a compressed file with the FastAPI code, normally from <a href="https://pypi.org/project/fastapi/" class="external-link" target="_blank">PyPI</a>.

It will also **download** files for other packages that FastAPI depends on.

Then it will **extract** all those files and put them in a directory in your computer.

{* ../../docs_src/custom_response/tutorial001b.py hl[2,7] *}

/// info

The parameter `response_class` will also be used to define the "media type" of the response.

In this case, the HTTP header `Content-Type` will be set to `application/json`.

And it will be documented as such in OpenAPI.

///

/// tip

The `ORJSONResponse` is only available in FastAPI, not in Starlette.

///

<img src="/img/tutorial/separate-openapi-schemas/image02.png">
</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

That means that **any value** read in Python from an environment variable **will be a `str`**, and any conversion to a different type or any validation has to be done in code.

      <description><![CDATA[
        This is the file specification used to activate a profile. The missing value will be a the location
        of a file that needs to exist, and if it doesn't the profile must run.  On the other hand exists will test
        for the existence of the file and if it is there will run the profile.
      ]]></description>
      <fields>
        <field>
          <name>missing</name>

   * and column pair, they will be combined with the specified merging function in encounter order.
   *
   * <p>The returned {@code Collector} will throw a {@code NullPointerException} at collection time
   * if the row, column, value, or merging functions return null on any input.
   *
   * @since 33.2.0 (available since 21.0 in guava-jre)
   */
  @IgnoreJRERequirement // Users will use this only if they're already using streams.

        * In requests, a list will be read, eliminating duplicates and converting it to a `set`.
        * In responses, the `set` will be converted to a `list`.
        * The generated schema will specify that the `set` values are unique (using JSON Schema's `uniqueItems`).
* `bytes`:
    * Standard Python `bytes`.
    * In requests and responses will be treated as `str`.