/**
 * Pre-handshake / reconnect outbox.
 *
 * Buffers frames produced while the WebSocket isn't OPEN and replays them
 * in FIFO order on `flush(send)`. Capped to defend against OOM if the
 * bridge is unreachable for an extended period.
 *
 * `sticky` marks frames that must survive eviction even when the outbox
 * is full — currently used for rrweb chunks containing a FullSnapshot
 * (type:2) baseline. Without this protection, the FullSnapshot — being
 * the oldest frame in the outbox — was always the first to be FIFO-
 * evicted under load, leaving the session permanently unreplayable.
 * Eviction only touches sticky frames as a last resort (all remaining
 * frames are sticky and we still exceed cap).
 */
export declare class Outbox {
    private readonly maxFrames;
    private readonly maxBytes;
    private entries;
    private bytes;
    constructor(maxFrames: number, maxBytes: number);
    /** Current buffered frame count. */
    get size(): number;
    /** Current buffered byte size. */
    get byteSize(): number;
    /** Inspect entries without exposing the underlying mutable array. */
    snapshot(): ReadonlyArray<{
        payload: string;
        sticky: boolean;
    }>;
    enqueue(payload: string, sticky: boolean): void;
    /**
     * Drain FIFO into `send`. If `send` throws (or returns false), keep the
     * frame in the queue and bail — caller will retry on next flush.
     */
    flush(send: (payload: string) => boolean | void): void;
}