import { OperatorFunction } from 'rxjs';
import { BuilderState } from '../types';
/**
 * Operator function that transforms a source Observable into an Observable of BuilderState.
 * It emits a BuilderPending state at the start, then a BuilderDone state when the source emits,
 * and a BuilderError state if the source errors out.
 * It also manages a global stack of pending builders.
 * @param stage
 * @param tag
 * @template T The type of the source Observable.
 * @returns {OperatorFunction<T, BuilderState<T>>} An OperatorFunction that can be used with pipe.
 */
export declare function builderState<T>(tag: string): OperatorFunction<T, BuilderState<T>>;