/**
     * @return true if the <b>debug</b> error level is enabled
     */
    boolean isDebugEnabled();

    /**
     * Send a message to the user in the <b>debug</b> error level.
     *
     * @param content
     */
    void debug(CharSequence content);

    /**
     * Send a message (and accompanying exception) to the user in the <b>debug</b> error level.<br>

import org.dbflute.mail.send.SMailDeliveryDepartment;
import org.dbflute.mail.send.SMailPostalMotorbike;
import org.dbflute.mail.send.SMailPostalParkingLot;
import org.dbflute.mail.send.SMailPostalPersonnel;
import org.dbflute.mail.send.embedded.personnel.SMailDogmaticPostalPersonnel;
import org.dbflute.mail.send.embedded.receptionist.SMailConventionReceptionist;
import org.dbflute.mail.send.supplement.async.SMailAsyncStrategy;

        // 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);

    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").
    """

        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));

            // 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

    }

    /**
     * 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
     */

            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),

                log.warn("Failed to pre-allocate receive buffer", e);
            }
        }

        log.info("Initialized RDMA buffer pool with {} send and {} receive buffers", availableSendRegions.size(),
                availableReceiveRegions.size());
    }

    /**
     * Get a send region from the pool or allocate a new one
     *
     * @param minSize minimum required size
     * @return memory region for sending

        // Mock for ensureOpen to reopen file
        when(mockFile.openUnshared(anyInt(), anyInt(), anyInt(), anyInt(), anyInt())).thenReturn(mockFileHandle);

        when(mockTreeHandle.send(any(Smb2WriteRequest.class), any())).thenReturn(mockWriteResponse);
        when(mockWriteResponse.getCount()).thenReturn(1);

        outputStream = new SmbFileOutputStream(mockFile, mockTreeHandle, mockFileHandle,