/**
 * Error message used when a connection is closed.
 *
 * This mirrors the constant exported by ioredis (`ioredis/built/utils`) but is
 * defined locally so that BullMQ can be used without ioredis installed (for
 * example, when using the PostgreSQL backend).
 */
export declare const CONNECTION_CLOSED_ERROR_MSG = "Connection is closed.";
/**
 * Thrown by any BullMQ Redis adapter (ioredis, node-redis, Bun, …) when a
 * command fails because the connection is already closed or was closed
 * mid-flight.
 *
 * Using a single well-known class lets {@link isNotConnectionError} do a
 * structural `instanceof` check rather than fragile message-substring matching.
 */
export declare class ConnectionClosedError extends Error {
    readonly cause?: unknown;
    constructor(message?: string, cause?: unknown);
}