function errorHandled(req, err) {
  const txInfo = getTransactionInfo(this, req)
  if (txInfo && txInfo.error === err) {
    txInfo.errorHandled = true
  }
}
Indicates that the given error has been handled for this request.

@memberof WebFrameworkShim.prototype
@param {Request} req - The request which caused the error.
@param {*}       err - The error which has been handled.
@see WebFrameworkShim#noticeError
@see WebFrameworkShim#setErrorPredicate