import { MiddlewareItem } from '../model';
import { NumberLike, TransactionParams } from '../../interfaces';
import { SubscribableOrPromise } from 'rxjs';
export declare type GasPriceLoader = (req: TransactionParams) => SubscribableOrPromise<NumberLike | undefined>;
export declare function gasPriceMiddleware(loader: GasPriceLoader): MiddlewareItem;