Let's look at how we can make that work.

## pytest.mark.anyio { #pytest-mark-anyio }

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX { #httpx }

 *
 * All event methods must execute fast, without external locking, cannot throw exceptions,
 * attempt to mutate the event parameters, or be reentrant back into the client.
 * Any IO - writing to files or network should be done asynchronously.
 */
internal abstract class ConnectionListener {
  /**
   * Invoked as soon as a call causes a connection to be started.
   */
  open fun connectStart(
    route: Route,
    call: Call,
  ) {}

   * calls returns to zero).
   *
   * Note: The time at which a [call][Call] is considered idle is different depending on whether it
   * 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.

    NoOpService service1 = new NoOpService();
    // This service will start service1 when addListener is called.  This simulates service1 being
    // started asynchronously.
    Service service2 =
        new Service() {
          final NoOpService delegate = new NoOpService();

          @Override
          public final void addListener(Listener listener, Executor executor) {

//     it defaults to defaultTTL.
//
// This function defines an onEvicted callback that is invoked when a cache entry is evicted.
// The callback ensures that if the evicted value (v) is not nil, its Close method is called asynchronously
// to release associated resources.
//
// Returns:
//   - A Store instance implemented by lruStore, which internally uses an LRU cache with the specified size,
//     eviction callback, and TTL.

 *         } catch (TimeoutException timeout) {
 *           // stopping timed out
 *         }
 *       }
 *     });
 *     manager.startAsync();  // start all the services asynchronously
 *   }
 * }
 * }
 *
 * <p>This class uses the ServiceManager's methods to start all of its services, to respond to

 *         } catch (TimeoutException timeout) {
 *           // stopping timed out
 *         }
 *       }
 *     });
 *     manager.startAsync();  // start all the services asynchronously
 *   }
 * }
 * }
 *
 * <p>This class uses the ServiceManager's methods to start all of its services, to respond to

import org.jspecify.annotations.Nullable;

/**
 * A step in a pipeline of an asynchronous computation. When the last step in the computation is
 * complete, some objects captured during the computation are closed.
 *
 * <p>A pipeline of {@code ClosingFuture}s is a tree of steps. Each step represents either an
 * asynchronously-computed intermediate value, or else an exception that indicates the failure or

/// tip

Notice that here as we are using standard `open()` that doesn't support `async` and `await`, we declare the path operation with normal `def`.

///

### `FileResponse` { #fileresponse }

Asynchronously streams a file as the response.

Takes a different set of arguments to instantiate than the other response types:

* `path` - The file path to the file to stream.

      receivedCloseCode = code
      receivedCloseReason = reason
    }

    listener.onClosing(this, code, reason)
  }

  // Writer methods to enqueue frames. They'll be sent asynchronously by the writer thread.

  override fun send(text: String): Boolean = send(text.encodeUtf8(), OPCODE_TEXT)

  override fun send(bytes: ByteString): Boolean = send(bytes, OPCODE_BINARY)