import type { LanguageModelV4StreamResult } from "@ai-sdk/provider";
import type { FallbackStreamArgs } from "./stream-types.js";
export type FallbackPumpConfig = Pick<FallbackStreamArgs, "attemptsStarted" | "attemptTimeout" | "backoff" | "budgetFailureObserved" | "budgetSuppressed" | "firstContentTimeout" | "firstResult" | "logicalId" | "maxAttempts" | "options" | "priorErrors" | "retryAfterOutput" | "startAttemptStartedAt" | "startIndex" | "startInFlight" | "startOrderingToken" | "strictStreamValidation" | "totalDeadline" | "totalTimeout">;
export declare function snapshotFallbackPumpConfig(source: FallbackStreamArgs, candidateCount: number, firstResult: LanguageModelV4StreamResult): FallbackPumpConfig;
/**
 * Wrap a stream result so a mid-stream failure transparently falls back to the
 * next candidate. The `request`/`response` metadata getters track whichever
 * candidate is producing the live stream — best-effort, since a consumer that
 * snapshots them at stream-open (as the AI SDK does) keeps the first candidate's
 * values across a later fallback.
 */