import type { GroupXEnvelope } from "../../core/envelope.js";
export declare const SSE_HEARTBEAT_FRAME = ": heartbeat\n\n";
export declare function assertSseEnvelope(envelope: GroupXEnvelope): void;
/** Encode one complete GroupX envelope as one SSE event. */
export declare function encodeSseEnvelope(envelope: GroupXEnvelope): string;
export declare function sseFrameBytes(frame: string): number;
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