type StreamChunk = string | Uint8Array | ArrayBuffer;
/** Server-side: where the writer sends text chunks. */
interface IOStreamTransport {
    send(chunk: string | Uint8Array): void | Promise<void>;
}
/**
 * Client-side: a source of bytes/text chunks.
 *
 * Supported shapes:
 * - string
 * - Iterable<StreamChunk>
 * - AsyncIterable<StreamChunk>
 * - Web ReadableStream<Uint8Array>
 * - Node.js Readable (AsyncIterable<Uint8Array|string>)
 */
type IOStreamSource = string | Iterable<StreamChunk> | AsyncIterable<StreamChunk> | ReadableStream<Uint8Array> | AsyncIterable<Uint8Array | string>;
interface StreamItem<T = any> {
    data: T;
    schemaName: string;
    index: number;
    error?: Error;
}
interface StreamReaderOptions {
    /** Optional default schema name if header does not provide $schema. */
    defaultSchema?: string;
    /**
     * Soft guardrails for streaming buffers.
     * This is not a security boundary, but prevents accidental unbounded growth.
     */
    maxBufferedChars?: number;
}
interface StreamWriterOptions {
    /** Default: true. If false, schemas are not written into the header. */
    includeSchemas?: boolean;
    /** If set, inserts a stable hash/id into header metadata (design hook). */
    defsId?: string;
    /**
     * How to handle validation/serialization errors during write().
     * - 'throw': Throw the error (default).
     * - 'ignore': Return empty string (skip the record).
     * - 'emit': Emit an error record (e.g. `!error { ... }`).
     */
    onError?: 'throw' | 'ignore' | 'emit';
}

export type { IOStreamSource, IOStreamTransport, StreamChunk, StreamItem, StreamReaderOptions, StreamWriterOptions };