import { IterableReadableStream } from "@langchain/core/utils/stream";
export declare const EventStreamContentType = "text/event-stream";
/**
 * Represents a message sent in an event stream
 * https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#Event_stream_format
 */
export interface EventSourceMessage {
    /** The event ID to set the EventSource object's last event ID value. */
    id: string;
    /** A string identifying the type of event described. */
    event: string;
    /** The event data */
    data: string;
    /** The reconnection interval (in milliseconds) to wait before retrying the connection */
    retry?: number;
}
/**
 * Converts a ReadableStream into a callback pattern.
 * @param stream The input ReadableStream.
 * @param onChunk A function that will be called on each new byte chunk in the stream.
 * @returns {Promise<void>} A promise that will be resolved when the stream closes.
 */
export declare function getBytes(stream: ReadableStream<Uint8Array>, onChunk: (arr: Uint8Array, flush?: boolean) => void): Promise<void>;
/**
 * Parses arbitary byte chunks into EventSource line buffers.
 * Each line should be of the format "field: value" and ends with \r, \n, or \r\n.
 * @param onLine A function that will be called on each new EventSource line.
 * @returns A function that should be called for each incoming byte chunk.
 */
export declare function getLines(onLine: (line: Uint8Array, fieldLength: number, flush?: boolean) => void): (arr: Uint8Array, flush?: boolean) => void;
/**
 * Parses line buffers into EventSourceMessages.
 * @param onId A function that will be called on each `id` field.
 * @param onRetry A function that will be called on each `retry` field.
 * @param onMessage A function that will be called on each message.
 * @returns A function that should be called for each incoming line buffer.
 */
export declare function getMessages(onMessage?: (msg: EventSourceMessage) => void, onId?: (id: string) => void, onRetry?: (retry: number) => void): (line: Uint8Array, fieldLength: number, flush?: boolean) => void;
export declare function convertEventStreamToIterableReadableDataStream(stream: ReadableStream): IterableReadableStream<any>;