import { ActionSource, FindActionSourceConstraints } from "./ActionSource.js";
/**
 * Find an available free run source subject to constraints.
 *
 * @param constraints Preexisting constraints that restrict possible sources.
 * @returns Free run source satisfying constraints, or null.
 */
export declare function tryFindFreeRun(constraints?: FindActionSourceConstraints): ActionSource | null;
/**
 * Ensure an available free run source subject to constraints.
 * Throws an error if no source can be found.
 *
 * @param constraints Preexisting constraints that restrict possible sources.
 * @returns Free run source satisfying constraints.
 */
export declare function ensureFreeRun(constraints?: FindActionSourceConstraints): ActionSource;