aget_delta_channel_history(
self,
*,
config: RunnableConfig,
channels: Sequence[str]
) -> Fast-path override of BaseCheckpointSaver.aget_delta_channel_history.
See SqliteSaver.get_delta_channel_history for design notes; this
is the async equivalent using aiosqlite cursors. Stage 1 pages
the parent chain newest-first and Python-deserializes each
checkpoint blob to find per-channel snapshots; stage 2 fetches
only the relevant writes via per-channel UNION ALL.