This gives you a lot of flexibility. You can return any data type, override any data declaration or validation, etc.

## Using the `jsonable_encoder` in a `Response`

Because **FastAPI** doesn't make any changes to a `Response` you return, you have to make sure its contents are ready for it.

{!../../docs_src/middleware/tutorial001.py!}
```

/// tip

Here we use <a href="https://docs.python.org/3/library/time.html#time.perf_counter" class="external-link" target="_blank">`time.perf_counter()`</a> instead of `time.time()` because it can be more precise for these use cases. 🤓

///

## Other middlewares

      }
      for (futureTask in futureTasks) {
        if (futureTask is AwaitIdleTask) {
          return futureTask.latch
        }
      }

      // Don't delegate to schedule() because that enforces shutdown rules.
      val newTask = AwaitIdleTask()
      if (scheduleAndDecide(newTask, 0L, recurrence = false)) {
        taskRunner.kickCoordinator(this)
      }
      return newTask.latch
    }

  /** Maximum size of a compact hash-based collection (2^30 - 1 because 0 is UNSET). */
  static final int MAX_SIZE = Ints.MAX_POWER_OF_TWO - 1;

  /** Default size of a compact hash-based collection. */
  static final int DEFAULT_SIZE = 3;

  /**
   * Minimum size of the hash table of a compact hash-based collection. Because small hash tables

      } else {
        utf8Length += encodedLengthGeneral(sequence, i);
        break;
      }
    }

    if (utf8Length < utf16Length) {
      // Necessary and sufficient condition for overflow because of maximum 3x expansion
      throw new IllegalArgumentException(
          "UTF-8 length does not fit in int: " + (utf8Length + (1L << 32)));
    }
    return utf8Length;
  }

 * </pre>
 * 
 * the access check would fail because the direct ACE has an access mask
 * of <tt>0x001200A9</tt> which doesn't have the
 * <tt>FILE_WRITE_DATA</tt> bit on (bit <tt>0x00000002</tt>). Actually, this isn't quite correct. If
 * <tt>WNET\alice</tt> is in the local <tt>Administrators</tt> group the access check
 * will succeed because the inherited ACE allows local <tt>Administrators</tt>

     * this method should provide all changes (size of that buffer can be adjusted through
     * {@link jcifs.Configuration#getNotifyBufferSize()}).
     * If the server cannot fulfill the request because the changes did not fit the buffer
     * it will return an empty list of changes.
     * 
     * @return changes since the last invocation
     * @throws CIFSException
     */

This is due to Java's use of reflection and the need to maintain a lot of metadata.

- **Size of Serialized Data:**
Java serialization tends to produce larger serialized objects because it includes class metadata and other overhead.

- **Flexibility and Control:**

  else
    TAG="pr-${KOKORO_GITHUB_PULL_REQUEST_NUMBER}"
  fi
fi

AR_IMAGE_PATH="us-central1-docker.pkg.dev/tensorflow-sigs/tensorflow/build-arm64"

# Build for both JAX and TF usage.  We do these in one place because they share
# almost all of the same cache layers
export DOCKER_BUILDKIT=1
for target in jax tf; do
  AR_IMAGE="$AR_IMAGE_PATH:$target-$TAG"
  docker pull "$AR_IMAGE" || true

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

```console
$ pip install python-multipart
```

This is because uploaded files are sent as "form data".

///

## Import `File`

Import `File` and `UploadFile` from `fastapi`:

//// tab | Python 3.9+

```Python hl_lines="3"