And this path operation will:

    * Send the invoice to the client.
    * Collect the money from the client.
    * Send a notification back to the API user (the external developer), as a callback.
        * At this point is that the API will somehow send a POST request to the
            external API with the notification of the invoice event
            (e.g. "payment successful").
    """

        async with AsyncExitStack() as stack:
            scope[self.context_name] = stack

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3
    Client->>Client: Process Item 2
    App->>Client: Send Item 3
    Client->>Client: Process Item 3
    Note over App: Keeps producing...
    Note over Client: Keeps consuming...

            // notification
            try {
                crawler.sendMail(infoMap);
            } catch (final Exception e) {
                logger.warn("Failed to send notification mail.", e);
            }

        }
    }

    /**
     * Sends email notification with crawling results and statistics.
     * The email contains detailed information about the crawling session including

        // Stub tree send for varargs
        when(treeConnection.send(eq(resourceLoc), any(CommonServerMessageBlockRequest.class), isNull(), any(RequestParam[].class)))
                .thenReturn(resp);

        CommonServerMessageBlockResponse out = handle.send(req, RequestParam.NO_RETRY);
        assertSame(resp, out);

    server.send(message3)
    clientListener.assertTextMessage(message3)

    // Empty client to server message.
    val message4 = ""
    client.send(message4)
    serverListener.assertTextMessage(message4)

    // Server to client message that shares context with message1.
    val message5 = message1 + message1
    server.send(message5)
    clientListener.assertTextMessage(message5)

        assertFalse(it.hasNext(), "Iterator should be exhausted");

        // Close explicitly to exercise doCloseInternal
        it.close();

        // Verify interactions: one create, two additional directory queries (for fetchMore), one close
        verify(tree, times(1)).send(argThat((Request<?> r) -> r instanceof Smb2CreateRequest));

            when(mockFile.getType()).thenReturn(SmbConstants.TYPE_NAMED_PIPE);

            // th.send(request, response, ...) throws SmbException with NT_STATUS_PIPE_BROKEN
            doThrow(new SmbException(NtStatus.NT_STATUS_PIPE_BROKEN, false)).when(mockTree)
                    .send(any(jcifs.internal.CommonServerMessageBlockRequest.class),

    }
    
    /**
     * Establish RDMA connection
     */
    public abstract void connect() throws IOException;
    
    /**
     * Send data using RDMA
     */
    public abstract void send(ByteBuffer data, RdmaMemoryRegion region) throws IOException;
    
    /**
     * Receive data using RDMA  
     */
    public abstract ByteBuffer receive(int timeout) throws IOException;

                curReq = next;
                curResp = next.getResponse();
            }
        }
    }

    /**
     * Sends a request and manages the response handling.
     *
     * @param <T> the response type
     * @param request the request to send
     * @param response the response object to populate
     * @param params additional parameters for the request