import { EIP1193ProviderFunc, JsonRpcResponseCallback, JsonRpcMiddlewareHandler, JsonRpcRequest } from "../types.js";
export declare class SingleflightMiddleware implements JsonRpcMiddlewareHandler {
    private singleflightJsonRpcMethods;
    inflight: {
        [key: string]: {
            id: number;
            callback: JsonRpcResponseCallback;
        }[];
    };
    constructor();
    requestHandler: (next: EIP1193ProviderFunc) => (request: JsonRpcRequest) => Promise<any>;
    requestKey: (method: string, params: any[], chainId?: number) => string;
}