/**
 * Internal transport interface used by `MessagingClient`. Abstracts the
 * WebSocket, SSE-fallback, and WebTransport lanes behind a single
 * lifecycle surface so the client can pick a lane at init time without
 * the rest of the SDK caring which one is in use.
 *
 * Public consumers of the SDK continue to use the standalone primitives
 * (`SseTransport`, `WebTransportTransport`); this interface is an internal
 * adapter target only.
 */
export interface MessagingTransportClose {
    code: number;
    reason: string;
}
export interface MessagingTransportEvents {
    onOpen(handler: () => void): void;
    onFrame(handler: (bytes: Uint8Array) => void): void;
    onClose(handler: (info: MessagingTransportClose) => void): void;
    onError(handler: (err: Error) => void): void;
}
export interface MessagingTransport extends MessagingTransportEvents {
    /** Human-readable transport name, mirrors the `/api/info.transports` token. */
    readonly name: 'ws' | 'sse' | 'wt';
    /** Open the underlying stream. Resolves once frames can be sent and received. */
    connect(): Promise<void>;
    /** Send a raw protobuf frame (no framing of its own). */
    send(bytes: Uint8Array): void;
    /** True if the transport can accept `send()` right now. */
    isOpen(): boolean;
    /** Close the stream. Idempotent. `code`/`reason` are best-effort hints. */
    close(code?: number, reason?: string): void;
}
export type MessagingTransportSelection = 'ws' | 'sse' | 'wt' | 'auto';