import { StashedMessage } from "./actor.js";
export type MailboxOverflowStrategy = "drop-newest" | "drop-oldest" | "error";
export interface MailboxConfig {
    /** Maximum number of messages. undefined = unbounded (default, backwards-compatible) */
    maxSize?: number;
    /** What to do when mailbox is full. Default: "drop-newest" */
    overflowStrategy?: MailboxOverflowStrategy;
}
export declare const DEFAULT_MAILBOX_CONFIG: MailboxConfig;
/**
 * Ring-buffer backed mailbox with O(1) enqueue and dequeue.
 *
 * The buffer grows dynamically (doubles) when full, avoiding the O(n)
 * cost of Array.shift() that dominated the previous implementation.
 * For bounded mailboxes, the ring never exceeds maxSize.
 */
export declare class BoundedMailbox {
    private readonly maxSize?;
    private readonly overflowStrategy;
    private buf;
    private head;
    private tail;
    private size;
    private droppedCount;
    constructor(config?: MailboxConfig);
    get length(): number;
    get dropped(): number;
    get isFull(): boolean;
    get capacity(): number | undefined;
    enqueue(msg: StashedMessage): boolean;
    dequeue(): StashedMessage | undefined;
    unshift(...msgs: StashedMessage[]): void;
    clear(): void;
    drain(): StashedMessage[];
    toArray(): StashedMessage[];
    replaceWith(msgs: StashedMessage[]): void;
    [Symbol.iterator](): Iterator<StashedMessage>;
    /** Double the internal buffer, preserving element order. */
    private grow;
}
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