message: Remove promise wrapping the save function
diff: @@ -59,15 +59,14 @@ export class HistoryFile {
  }
  }
  - public save(): Promise<void> {
  - return new Promise<void>(async (resolve, reject) => {
  + public async save(): Promise<void> {
  try {
  if (!(await util.promisify(fs.exists)(this._historyDir))) {
  mkdirp.sync(this._historyDir, 0o775);
  }
  } catch (err) {
  logger.error(`Failed to create directory. path=${this._historyDir}. err=${err}.`);
  - reject(err);
  + throw err;
  }
  try {
  @@ -78,11 +77,8 @@ export class HistoryFile {
  );
  } catch (err) {
  logger.error(`Failed to save history. path=${this._historyDir}. err=${err}.`);
  - reject(err);
  + throw err;
  }
  -
  - resolve();
  - });
  }
  public async load() {
  