*/
class Exchange(
  internal val call: RealCall,
  internal val eventListener: EventListener,
  internal val finder: ExchangeFinder,
  private val codec: ExchangeCodec,
) {
  /** True if the request body need not complete before the response body starts. */
  internal var isDuplex: Boolean = false
    private set

  /** True if there was an exception on the connection to the peer. */
  internal var hasFailure: Boolean = false

    }

    /**
     * Get the preferred size for send operations
     *
     * @return preferred send size in bytes
     */
    public int getPreferredSendSize() {
        return preferredSendSize;
    }

    /**
     * Set the preferred size for send operations
     *
     * @param preferredSendSize preferred send size in bytes
     */

### Import typing's `List` { #import-typings-list }

In Python 3.9 and above you can use the standard `list` to declare these type annotations as we'll see below. 💡

But in Python versions before 3.9 (3.6 and above), you first need to import `List` from standard Python's `typing` module:

{* ../../docs_src/body_nested_models/tutorial002.py hl[1] *}

First of all, be nice. 😊

You probably are super nice if you were added to the team, but it's worth mentioning it. 🤓

### When Things are Difficult

When things are great, everything is easier, so that doesn't need much instructions. But when things are difficult, here are some guidelines.

   * environment? If the latter, maybe write a custom Executor that avoids failing the test when it
   * sees an Error?
   */
  @AndroidIncompatible
  public void testTaskThrowsError() throws Exception {
    class MyError extends Error {}
    CyclicBarrier barrier = new CyclicBarrier(2);
    // we need to make sure the error gets thrown on a different thread.
    ExecutorService service = newSingleThreadExecutor();
    try {

        /* The Filter can only work with NTLMv1 as it uses a man-in-the-middle
         * techinque that NTLMv2 specifically thwarts. A real NTLM Filter would
         * need to do a NETLOGON RPC that JCIFS will likely never implement
         * because it requires a lot of extra crypto not used by CIFS.
         */
        Config.setProperty("jcifs.smb1.smb.lmCompatibility", "0");

# ----------------------------------------------------------
#                                                      Mail
#                                                     ------
# Does it send mock mail? (true: no send actually, logging only)
mail.send.mock = true

# SMTP server settings for main: host:port
mail.smtp.server.main.host.and.port = localhost:25

# The prefix of subject to show test environment or not

Up to now, you have been declaring the parts of the request that you need with their types.

Taking data from:

* The path as parameters.
* Headers.
* Cookies.
* etc.

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

If you want to play with JWT tokens and see how they work, check <a href="https://jwt.io/" class="external-link" target="_blank">https://jwt.io</a>.

## Install `PyJWT` { #install-pyjwt }

We need to install `PyJWT` to generate and verify the JWT tokens in Python.

import jcifs.internal.util.SMBUtil;

/**
 * SMB1 Seek command response implementation.
 * Handles server responses to file seek operations, returning the new file
 * position after a seek request in SMB1 protocol file operations.
 *
 * @author mbechler
 */
public class SmbComSeekResponse extends ServerMessageBlock {

    private long offset;

    /**
     * Constructs a seek response.
     *