import type { LanguageModelV4StreamPart, LanguageModelV4StreamResult } from "@ai-sdk/provider";
export declare class IncompleteModelStreamError extends Error {
    readonly code = "incomplete_model_stream";
    constructor();
}
export declare class EmptyModelStreamError extends Error {
    readonly code = "empty_model_response";
    constructor();
}
export declare class StreamPreludeOverflowError extends Error {
    readonly code = "stream_prelude_overflow";
    constructor();
}
export declare class InvalidModelStreamError extends Error {
    readonly code = "invalid_model_stream";
    constructor(message: string, cause?: unknown);
}
export declare class RouterStreamError extends Error {
    readonly code = "stream_unavailable";
    constructor(cause: unknown);
}
export declare class CleanedStreamSetupError extends Error {
    constructor(cause: unknown);
}
export interface CapturedReader {
    cancel(reason?: unknown): Promise<void>;
    read(): Promise<ReadableStreamReadResult<LanguageModelV4StreamPart>>;
    releaseLock(): void;
}
export declare function snapshotReadResult(value: unknown): ReadableStreamReadResult<LanguageModelV4StreamPart>;
export declare function tryReaderMethod(reader: object, method: "cancel" | "read" | "releaseLock"): {
    error?: unknown;
    value?: unknown;
};
export declare function cleanupPartialReader(reader: object, cancel: unknown, releaseLock: unknown): void;
export declare function cleanupUnreadableStream(stream: object, reason: unknown): void;
export declare function captureReader(result: LanguageModelV4StreamResult): CapturedReader;
/** Cancel an upstream reader, swallowing a sync throw or async rejection. */
export declare const cancelledReaders: WeakSet<CapturedReader>;
export declare function cancelQuietly(reader: CapturedReader | null, reason: unknown): void;
export declare const releasedReaderLocks: WeakSet<CapturedReader>;
export declare function releaseReaderLockQuietly(reader: CapturedReader): void;
export declare function cancelAndReleaseReaderQuietly(reader: CapturedReader | null, reason: unknown): void;