export declare function isHangingPromiseRejectionError(err: unknown): err is HangingPromiseRejectionError; declare class HangingPromiseRejectionError extends Error { readonly route: string; readonly expression: string; readonly digest = "HANGING_PROMISE_REJECTION"; constructor(route: string, expression: string); } export declare function makeDevtoolsIOAwarePromise(underlying: T): Promise; export {};