/**
 * Handoff result returned by the host extension's `AuthPlugin`.
 *
 * @internal Low-level transport detail consumed by `embeddedFabricLogin`.
 */
export interface PostMessageHandoffResult {
    /** Single-use handoff code to exchange for tokens. */
    handoffCode: string;
    /** Opaque nonce echoed back for correlation. */
    state: string;
}
/**
 * PostMessage transport for embedded (iframe) auth.
 *
 * Sends a `fabric-auth` / `auth.requestHandoff` message to the parent
 * window and waits for a correlated response carrying the handoff code.
 *
 * Delegates the low-level postMessage send/receive/correlate to
 * `sendBridgeRequest` from `@microsoft/fabric-embedded-host`.
 *
 * @param params - Handoff request parameters:
 *   - `callbackUrl`: The callback origin where the SPA is hosted.
 *   - `codeChallenge`: PKCE S256 code challenge.
 *   - `codeChallengeMethod`: Always `"S256"`.
 *   - `state`: Opaque nonce for CSRF/correlation.
 *   - `timeoutMs`: Response timeout in milliseconds (default 30 000).
 * @returns Promise resolving with the handoff code and state.
 * @throws `AuthError` - On timeout, error response, or missing parent.
 * @internal Low-level transport helper used by `embeddedFabricLogin`; not a
 * supported public API.
 */
export declare function requestHandoff(params: {
    callbackUrl: string;
    codeChallenge: string;
    codeChallengeMethod: string;
    state: string;
    timeoutMs?: number;
}): Promise<PostMessageHandoffResult>;
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