use crateSnapshotConfig;
/// Configuration for a [`GraphState`](super::GraphState).
///
/// Wraps a [`SnapshotConfig`] that controls where snapshots are stored, which
/// format and compression they use, and how many past snapshots to retain.
///
/// **Important**: the `key` field of the inner [`SnapshotConfig`] must be `None`.
/// [`GraphState`](super::GraphState) manages the key itself; passing a pre-set key
/// will cause [`GraphStateBuilder::init`](super::GraphStateBuilder::init) to return
/// [`SnapshotError::InvalidKey`](crate::snapshot::SnapshotError::InvalidKey).