import { ClientConfig, Message, PublishOptions, PubSub, SubscriberOptions, Subscription } from '@google-cloud/pubsub';
import { CustomTransportStrategy, Server } from '@nestjs/microservices';
import { Logger } from '@nestjs/common';
import { GCPubSubOptions } from './gc-pubsub.interface';
import { GCPubSubEvents } from './gc-pubsub.events';
export declare class GCPubSubServer extends Server<GCPubSubEvents> implements CustomTransportStrategy {
    protected readonly options: GCPubSubOptions;
    protected logger: Logger;
    protected readonly clientConfig: ClientConfig;
    protected readonly topicName: string;
    protected readonly publisherConfig: PublishOptions;
    protected readonly subscriptionName: string;
    protected readonly subscriberConfig: SubscriberOptions;
    protected readonly noAck: boolean;
    protected readonly replyTopics: Set<string>;
    protected readonly init: boolean;
    protected readonly checkExistence: boolean;
    protected readonly scopedEnvKey: string | null;
    protected readonly subscriptionFilter: string | undefined;
    protected pendingEventListeners: Array<{
        event: keyof GCPubSubEvents;
        callback: GCPubSubEvents[keyof GCPubSubEvents];
    }>;
    protected client: PubSub | null;
    protected subscription: Subscription | null;
    constructor(options: GCPubSubOptions);
    listen(callback: () => void): Promise<void>;
    close(): Promise<void>;
    handleMessage(message: Message): Promise<any>;
    sendMessage<T = any>(message: T, replyTo: string, id: string): Promise<void>;
    createIfNotExists(create: () => Promise<any>): Promise<void>;
    createClient(): PubSub;
    on<EventKey extends keyof GCPubSubEvents = keyof GCPubSubEvents, EventCallback extends GCPubSubEvents[EventKey] = GCPubSubEvents[EventKey]>(event: EventKey, callback: EventCallback): void;
    unwrap<T>(): T;
}