And also after the `response` is generated, before returning it.

For example, you could add a custom header `X-Process-Time` containing the time in seconds that it took to process the request and generate a response:

```Python hl_lines="10  12-13"
{!../../docs_src/middleware/tutorial001.py!}
```

/// tip

  // An update strategy to replace existing DaemonSet pods with new pods.
  // +optional
  optional DaemonSetUpdateStrategy updateStrategy = 3;

  // The minimum number of seconds for which a newly created DaemonSet pod should
  // be ready without any of its container crashing, for it to be considered
  // available. Defaults to 0 (pod will be considered available as soon as it
  // is ready).

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# WebSockets

When defining WebSockets, you normally declare a parameter of type `WebSocket` and with it you can read data from the client and send data to it.

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

/// tip

* `datetime.timedelta`:
    * A Python `datetime.timedelta`.
    * In requests and responses will be represented as a `float` of total seconds.
    * Pydantic also allows representing it as a "ISO 8601 time diff encoding", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#custom-serializers" class="external-link" target="_blank">see the docs for more info</a>.

import static java.util.concurrent.Executors.newCachedThreadPool;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Stopwatch;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;

        } else {
            Trans2FindFirst2 req = new Trans2FindFirst2( "\\", "*", SmbFile.ATTR_DIRECTORY );
            Trans2FindFirst2Response resp = new Trans2FindFirst2Response();
            tree.send( req, resp );
        }
    }

    /* 0 - not connected
     * 1 - connecting
     * 2 - connected
     * 3 - disconnecting
     */
    int connectionState;
    int uid;
    Vector trees;

    /* Should recover to be able to remove() after next(). */
    assertEquals("B", peekingIterator.next());
    peekingIterator.remove();
    assertEquals("Should have removed an element", 2, list.size());
    assertFalse("Second element should be gone", list.contains("B"));
  }

  static class ThrowsAtEndException extends RuntimeException {
    /* nothing */
  }

  /**

  private lateinit var client: OkHttpClient

  val listener = RecordingEventListener()

  fun setUp(mode: Pair<CancelMode, ConnectionType>) {
    this.cancelMode = mode.first
    this.connectionType = mode.second

    if (connectionType == H2) {
      platform.assumeHttp2Support()
    }

    // Sockets on some platforms can have large buffers that mean writes do not block when

            if (exitValue != 0) {
                final StringBuilder out = new StringBuilder();
                if (processTimeout) {
                    out.append("Process is terminated due to ").append(timeout).append(" second exceeded.\n");
                }
                out.append("Exit Code: ").append(exitValue).append("\nOutput:\n").append(it.getOutput());
                throw new JobProcessingException(out.toString());
            }