static FeignException errorExecuting(Request request, IOException cause) {
    final Long nonRetryable = null;
    return new RetryableException(
        -1,
        format("%s executing %s %s", cause.getMessage(), request.httpMethod(), request.url()),
        request.httpMethod(),
        cause,
        nonRetryable,
        request);
  }
The Response body.

@return an Optional wrapping the response body.
core/src/main/java/feign/FeignException.java