export type All = "*";
export type PendingWriteValue = unknown;
export type PendingWrite<Channel = string> = [Channel, PendingWriteValue];
export type CheckpointPendingWrite<TaskId = string> = [
    TaskId,
    ...PendingWrite<string>
];
/**
 * Additional details about the checkpoint, including the source, step, writes, and parents.
 *
 * @typeParam ExtraProperties - Optional additional properties to include in the metadata.
 */
export type CheckpointMetadata<ExtraProperties extends object = object> = {
    /**
     * The source of the checkpoint.
     * - "input": The checkpoint was created from an input to invoke/stream/batch.
     * - "loop": The checkpoint was created from inside the pregel loop.
     * - "update": The checkpoint was created from a manual state update.
     * - "fork": The checkpoint was created as a copy of another checkpoint.
     */
    source: "input" | "loop" | "update" | "fork";
    /**
     * The step number of the checkpoint.
     * -1 for the first "input" checkpoint.
     * 0 for the first "loop" checkpoint.
     * ... for the nth checkpoint afterwards.
     */
    step: number;
    /**
     * The IDs of the parent checkpoints.
     * Mapping from checkpoint namespace to checkpoint ID.
     */
    parents: Record<string, string>;
} & ExtraProperties;