/**
 * The configuration with which a traverser is created.
 */
export interface TraversalConfig {
    /**
     * The number of documents that will be traversed in each batch.
     *
     * @defaultValue 250
     */
    readonly batchSize: number;
    /**
     * The amount of time (in ms) to "sleep" before moving on to the next batch.
     *
     * @defaultValue 0
     */
    readonly sleepTimeBetweenBatches: number;
    /**
     * The maximum number of documents that will be traversed.
     *
     * @defaultValue `Infinity`
     */
    readonly maxDocCount: number;
    /**
     * The maximum number of batches that can be held in memory and processed concurrently.
     *
     * @remarks
     *
     * This field must be a positive integer representing the maximum number of batches that you wish
     * the traverser to process concurrently at any given time. The traverser will pause when the number
     * of batches being processed concurrently reaches this number and continue when a batch has been
     * processed. This means that the higher the value of `maxConcurrentBatchCount`, the more memory the
     * traverser will consume but also the faster it will finish the traversal.
     *
     * @example
     *
     * ```typescript
     * const projectsColRef = firestore().collection('projects');
     * const traverser = createTraverser(projectsColRef, {
     *   batchSize: 500,
     *   maxConcurrentBatchCount: 20,
     * });
     * ```
     *
     * By providing this config we have indicated that we want each batch to contain 500 documents and the
     * traverser to process 20 batches concurrently at any given time. This means we have ensured that our
     * machine can handle 500 * 20 = 10,000 documents in memory at any given time.
     *
     * @defaultValue 1
     */
    readonly maxConcurrentBatchCount: number;
    /**
     * The maximum number of times the traverser will retry processing a given batch, in case of an error.
     * By default, batches are not retried.
     *
     * @remarks
     *
     * This field must be a non-negative integer representing the maximum number of times the traverser will
     * retry processing a given batch. By default, the traverser invokes the batch callback only once i.e.
     * with 0 retries but, if `maxBatchRetryCount` > 0, it will keep invoking the callback until it succeeds
     * or the total number of retries reaches `maxBatchRetryCount`.
     *
     * @defaultValue 0
     */
    readonly maxBatchRetryCount: number;
    /**
     * A non-negative integer or a function that takes the 0-based index of the last trial and returns a
     * non-negative integer indicating the amount of time (in ms) to "sleep" before retrying processing
     * the current batch. This is useful if you want to implement something like exponential backoff.
     *
     * @defaultValue 1000
     */
    readonly sleepTimeBetweenTrials: number | ((lastTrialIndex: number) => number);
}