import type { PlatformAdapter } from './adapter.js';
import type { Destination, MessageRef } from './types.js';
import type { OpenOutputStreamOpts } from './output-stream.js';
/** Post a single text message and return its parent MessageRef.
 *  Creates a transient OutputStream, emits, flushes, and disposes. */
export declare function postOnce(adapter: PlatformAdapter, destination: Destination, text: string, opts?: OpenOutputStreamOpts): Promise<MessageRef | null>;