MemorySaver

Delete all checkpoints and writes associated with a specific thread ID.

Override: walk the parent chain ONCE for all requested channels using direct storage access.

Each channel terminates independently at the nearest ancestor whose stored channel_values[ch] is populated. Other channels keep walking until they find their own terminator or hit the root.

The seed value (whether a DeltaSnapshot or a plain pre-delta migration blob) is the value AT that ancestor, prior to its own pending writes that produce the child. Those on-path writes — including the ones stored on the terminating ancestor — are always collected and replayed on top of the seed, so a thread migrated from a pre-delta channel does not drop the writes saved under the migration boundary checkpoint.

Generate the next version ID for a channel.

Default is to use integer versions, incrementing by 1. If you override, you can use str/int/float versions, as long as they are monotonically increasing.

Store intermediate writes linked to a checkpoint.

Prevent JSON.stringify from traversing backend clients (e.g. pg Pool timers) when a checkpointer is present in runnable configurable.