export type E4Attribution = 'self' | 'other' | 'unknown';
export type E6Attribution = E4Attribution | 'idle';
export declare const TURN_TERMINAL_ERROR_CODES: ReadonlySet<string>;
export declare const NON_TERMINAL_CONTROL_ERROR_CODES: ReadonlySet<string>;
export declare function isTurnTerminalError(err: {
    code?: unknown;
    gatewayTurnId?: unknown;
} | undefined): boolean;
export declare function isNonTerminalControlError(err: {
    code?: string;
}): boolean;
export declare function readTurnAttribution(frame: {
    gatewayTurnId?: unknown;
    turnClientMsgId?: unknown;
}, msgId: string): E4Attribution;
export declare function readInFlightAttribution(session: Record<string, unknown>, msgId: string): E6Attribution | null;
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