export interface AsyncStorage<T> {
    run<R>(store: T, fn: () => R | Promise<R>): R | Promise<R>;
    getStore(): T | undefined;
    /**
     * Every store bound by a live `run`, oldest first.
     *
     * On an isolating runtime that is the current task's store alone,
     * because `AsyncLocalStorage` cannot enumerate other tasks and the
     * isolated world never needs it to. On the fallback it is the honest
     * answer the single slot cannot give — all concurrently live
     * bindings — so a reader can merge conservatively instead of
     * trusting whichever binding happens to sit in the slot. The array
     * is a snapshot; it does not track later binds or settles.
     */
    liveStores(): readonly T[];
}
/**
 * The browser storage: no task isolation, one frame stack per storage.
 *
 * `getStore` answers the newest live frame, so a read that interleaves
 * with another task's bind can still see that task's store — only real
 * isolation fixes that, which is what `liveStores` exists to route
 * around. What the stack does fix is the slot's two worse failures: a
 * settle removes its own frame rather than blind-restoring a saved
 * value, so an out-of-order settle can neither wipe a binding that is
 * still live nor strand a stale one after every run has finished.
 *
 * Exported for the fallback-mode tests, which mock `createAsyncContext`
 * with this class so the browser branch runs under node's test runner.
 */
export declare class FallbackStorage<T> implements AsyncStorage<T> {
    private frames;
    run<R>(s: T, fn: () => R | Promise<R>): R | Promise<R>;
    getStore(): T | undefined;
    liveStores(): readonly T[];
}
/**
 * Whether the storage isolates concurrent tasks, verified behaviorally
 * at module load rather than assumed from where the constructor came
 * from.
 *
 * `AsyncLocalStorage` gives every task its own store. The fallback is
 * one frame stack whose top a concurrent task can shadow, so a caller
 * that binds a store for concurrent work has to know which it got.
 */
export declare const asyncContextIsolatesTasks: boolean;
export declare function createAsyncContext<T>(): AsyncStorage<T>;
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