- Support for query parameters, headers, body (String or stream), compression, SSL configuration, proxies, and timeouts
- Automatic in-memory or on-disk caching of request/response bodies
- Synchronous and asynchronous (callback) execution
- Minimal dependencies (only Apache Commons IO)

## Installation

### Maven

Add the dependency to your `pom.xml` (replace `x.y.z` with the latest version):

```xml

   * was run [asynchronously][Call.enqueue] or [synchronously][Call.execute]. Asynchronous calls
   * become idle after the [onResponse][Callback.onResponse] or [onFailure][Callback.onFailure]
   * callback has returned. Synchronous calls become idle once [execute()][Call.execute] returns.
   * This means that if you are doing synchronous calls the network layer will not truly be idle

 * when responses are of an unexpected type or cannot be decoded.
 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *
 *  * For asynchronous calls made with [Call.enqueue], an [IOException] is propagated to the caller
 *    indicating that the call was canceled. The interceptor's exception is delivered to the current

Calls are executed in one of two ways:

 * **Synchronous:** your thread blocks until the response is readable.
 * **Asynchronous:** you enqueue the request on any thread, and get [called back](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-callback/) on another thread when the response is readable.

# Async Tests { #async-tests }

You have already seen how to test your **FastAPI** applications using the provided `TestClient`. Up to now, you have only seen how to write synchronous tests, without using `async` functions.

     *
     * @param config
     *            The configuration to use
     * @param mid
     *            The message ID of the request to cancel
     * @param asyncId
     *            The async ID for asynchronous operations (0 for synchronous)
     */
    public Smb2CancelRequest(final Configuration config, final long mid, final long asyncId) {
        super(config, SMB2_CANCEL);
        setMid(mid);
        setAsyncId(asyncId);

        return new Smb2SessionSetupResponse(cfg);
    }

    /**
     * Build a minimal SMB2 header for a response at the given offset.
     * The header is prepared as a synchronous response with server-to-redirector flag.
     */
    private void buildHeader(byte[] buf, int start, int status, int command, long sessionId) {

   * CacheLoader#reload}.
   *
   * <p>As the default implementation of {@link CacheLoader#reload} is synchronous, it is
   * recommended that users of this method override {@link CacheLoader#reload} with an asynchronous
   * implementation; otherwise refreshes will be performed during unrelated cache read and write
   * operations.
   *

   * response to the sender.
   *
   * @since 8.0
   */
  public static final byte NAK = 21;

  /**
   * Synchronous Idle: A communication control character used by a synchronous transmission system
   * in the absence of any other character to provide a signal from which synchronism may be
   * achieved or retained.
   *
   * @since 8.0
   */

Modern versions of Python have support for **"asynchronous code"** using something called **"coroutines"**, with **`async` and `await`** syntax.

Let's see that phrase by parts in the sections below:

* **Asynchronous Code**
* **`async` and `await`**
* **Coroutines**

## Asynchronous Code { #asynchronous-code }