code: func (f *fatalErrorHandler) FatalError(err error) {
  	f.mu.Lock()
  	defer f.mu.Unlock()
  	if !f.done {
  		f.done = true
  		close(f.donec)
  	}
  	f.err = err
  }
docs: // FatalError error is used in some rare situations where it does not make sense to
  // continue processing, to abort as soon as possible and log the error.