message: implement getFee
diff: @@ -10,6 +10,8 @@ import {
  } from "../generated/rpc/v1/account_info_pb";
  import { AccountAddress } from "../generated/rpc/v1/amount_pb";
  import { GetTxRequest, GetTxResponse } from "../generated/rpc/v1/tx_pb";
  +import { XRPDropsAmount } from "xpring-common-js/build/generated/rpc/v1/amount_pb";
  +import { GetFeeRequest } from "../generated/rpc/v1/fee_pb";
  /* global BigInt */
  @@ -175,6 +177,23 @@ class DefaultXpringClient implements XpringClientDecorator {
  return new GetTxResponseWrapper(getTxResponse);
  }
  +
  + private async getFee(): Promise<XRPDropsAmount> {
  + const getFeeRequest = new GetFeeRequest();
  +
  + const getFeeResponse = await this.networkClient.getFee(getFeeRequest);
  + const fee = getFeeResponse.getDrops();
  + if (!fee) {
  + throw new Error(XpringClientErrorMessages.malformedResponse);
  + }
  +
  + const minimumFee = fee.getMinimumFee();
  + if (!minimumFee) {
  + throw new Error(XpringClientErrorMessages.malformedResponse);
  + }
  +
  + return minimumFee;
  + }
  }
  export default DefaultXpringClient;
  