export type MuxCall<P> = (signal: AbortSignal, p: P) => void;
export type MuxTrainArg<T, P> = {
    /**
     * Wired to the internal group's halt handler.
     * Can prevent shutdown of an unused train, just delay.
     */
    halt?: (groupSignal: AbortSignal, resumeSignal: AbortSignal) => Promise<void>;
    /**
     * Called if an error occured trying to set up the train.
     */
    error?: (error: Error) => void;
    /**
     * Builds the train that passengers are connecting to.
     *
     * It is valid/encouraged for this to throw, or the `done` return to throw.
     */
    build(signal: AbortSignal): Promise<{
        target: T;
        done: Promise<any>;
    }>;
    /**
     * Connects this passenger to the current train.
     *
     * If this throws, the whole train will crash.
     * If the connection is dangerous, wrap in something that informs the {@link P}.
     */
    connect(signal: AbortSignal, t: T, p: P): void;
};
export declare function buildMuxTrain<T, P>(arg: MuxTrainArg<T, P>): MuxCall<P>;