export interface WebSocketMessageAdmission {
    readonly accepted: boolean;
    /**
     * Exact size when accepted, or a finite lower-bound sentinel when a string
     * is rejected early.
     */
    readonly sizeBytes: number;
}
/**
 * Return the wire-size boundary used for browser WebSocket message payloads.
 *
 * Strings are measured as UTF-8 rather than UTF-16 code units. ArrayBuffer
 * views use only their visible slice, and Blob payloads use their byte size
 * without materializing their contents.
 */
export declare function getWebSocketMessageSizeBytes(data: unknown): number;
/**
 * Check a WebSocket payload against a byte limit without scanning beyond the
 * admission boundary. Exact-at-limit payloads remain accepted.
 */
export declare function getWebSocketMessageAdmission(data: unknown, maximumBytes: number): WebSocketMessageAdmission;
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