from slack_sdk.models.messages.chunk import TaskUpdateChunk

streamer = client.chat_stream(
    channel="C0123456789",
    recipient_team_id="T0123456789",
    recipient_user_id="U0123456789",
    thread_ts="1234567890.123456",
    task_display_mode="timeline",
)

streamer.append(
    chunks=[
        TaskUpdateChunk(
            id="task-1",
            title="Processing...",
            status="in_progress",
        ),
    ],
)

streamer.stop(
    chunks=[
        TaskUpdateChunk(
            id="task-1",
            title="Done!",
            status="complete",
        ),
    ],
)

from slack_sdk.models.blocks import (
    RichTextBlock,
    RichTextElementParts,
    RichTextSectionElement,
    TaskCardBlock,
    UrlSourceElement,
)
...
client.chat_postMessage(
    channel="C0123456789",
    blocks=[
        TaskCardBlock(
            task_id="000",
            title="Living life well...",
            status="error",
            details=RichTextBlock(
                elements=[
                    RichTextSectionElement(
                        elements=[
                            RichTextElementParts.Text(text="Dreamt of touching grass"),
                        ],
                    ),
                ],
            ),
            sources=[
                UrlSourceElement(
                    text="An online encyclopedia",
                    url="https://wikipedia.org",
                ),
            ],
            output=RichTextBlock(
                elements=[
                    RichTextSectionElement(
                        elements=[
                            RichTextElementParts.Text(text="Good things once happened"),
                        ],
                    ),
                ],
            ),
        ),
    ],
)