export interface FeeDetail {
    fee: number;
    wait?: number;
}
export interface FeeDetails {
    slow: FeeDetail;
    average: FeeDetail;
    fast: FeeDetail;
}
export interface FeeProvider {
    /**
     * @return {Promise<FeeDetails>} Resolves with an
     *  identifier for the broadcasted transaction.
     *  Rejects with InvalidProviderResponseError if provider's response is invalid.
     */
    getFees(): Promise<FeeDetails>;
}