You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

 * This class simplifies communication for protocols that support
 * multiplexing requests. It encapsulates a stream and some protocol
 * knowledge (provided by a concrete subclass) so that connecting,
 * disconnecting, sending, and receiving can be syncronized
 * properly. Apparatus is provided to send and receive requests
 * concurrently.
 */

public abstract class Transport implements Runnable {

    /**
     * Default constructor for Transport.

        // Tree handle is released after close
        verify(tree, atLeastOnce()).release();
    }

    @Test
    @DisplayName("open(): server returns NO_SUCH_FILE after receiving response -> iterator empty, closed")
    void openHandlesNoSuchFileGracefully() throws Exception {
        when(tree.send(any(Trans2FindFirst2.class), any(Trans2FindFirst2Response.class))).thenAnswer((InvocationOnMock inv) -> {

            region.close();
            totalReleased.incrementAndGet();
        }
    }

    /**
     * Get a receive region from the pool or allocate a new one
     *
     * @return memory region for receiving
     * @throws IOException if allocation fails
     */
    public RdmaMemoryRegion getReceiveRegion() throws IOException {
        RdmaMemoryRegion region = availableReceiveRegions.poll();
        if (region != null) {

{* ../../docs_src/path_params/tutorial003.py hl[6,11] *}

Otherwise, the path for `/users/{user_id}` would match also for `/users/me`, "thinking" that it's receiving a parameter `user_id` with a value of `"me"`.

Similarly, you cannot redefine a path operation:

{* ../../docs_src/path_params/tutorial003b.py hl[6,11] *}

    private static final String WITNESS_SERVICE_UUID = "ccd8c074-d0e5-4a40-92b4-d074faa6ba28";
    private static final int DEFAULT_WITNESS_PORT = 135; // RPC endpoint mapper

    /**
     * Interface for receiving witness notifications and registration events.
     */
    public interface WitnessNotificationListener {
        /**
         * Called when a witness notification is received.
         *

    /**
     * Configures this request's body to be compressed when it is transmitted. This also adds the
     * 'Content-Encoding: gzip' header.
     *
     * Only use this method if you have prior knowledge that the receiving server supports
     * gzip-compressed requests.
     *
     * It is an error to call this multiple times on the same instance.
     *

    // retry, we return true and try a new route.
    return true
  }

  /**
   * Figures out the HTTP request to make in response to receiving [userResponse]. This will
   * either add authentication headers, follow redirects or handle a client request timeout. If a
   * follow-up is either unnecessary or not applicable, this returns null.
   */

 * registration. It is not a general-purpose publish-subscribe system, nor is it intended
 * for interprocess communication.
 *
 * <h2>Receiving Events</h2>
 *
 * <p>To receive events, an object should:
 *
 * <ol>
 *   <li>Expose a public method, known as the <i>event subscriber</i>, which accepts a single
 *       argument of the type of event desired;

* `upgrade`: Upgrades