/** Capability negotiation helper for GSP. */
/**
 * Per-member capability advertisement plus intersection / union queries
 * for negotiating optional features (codecs, extensions, version flags).
 */
export declare class CapabilitiesNegotiator {
    private readonly advertised;
    /** Record an advertisement (replaces any prior one). */
    advertise(memberId: number, capabilities: Iterable<string>): void;
    /** Remove a member's advertisement. */
    forget(memberId: number): void;
    /** Current advertisement for `memberId` (a copy). */
    capabilitiesOf(memberId: number): Set<string> | null;
    /** `true` iff every advertised member supports `capability`. */
    groupSupports(capability: string): boolean;
    /** Intersection — capabilities every member advertises (safe-to-use set). */
    intersection(): Set<string>;
    /** Union — every capability advertised by any member. */
    union(): Set<string>;
    /** Members that did not advertise `capability`. */
    missing(capability: string): number[];
    get size(): number;
}
//# sourceMappingURL=capabilities.d.ts.map