code: private void logRetryAttempt(ExecutionAttributes attrs) {
      IpcLogEntry logEntry = attrs.getAttribute(LOG_ENTRY);
      if (logEntry != null) {
        if (!isStatusSet(attrs)) {
          logEntry.markEnd().withStatus(IpcStatus.unexpected_error);
        }
        logEntry.log();
      }
    }
docs: If there is a retry, then {@code beforeTransmission} will be called with the previous
  attributes. This method will look for an existing entry and write out the log message.
  The log entry may not have been filled in with a status if no response was received,
  e.g., a connection exception. Since we do not have access to the failure, the status
  will get set to {@code unexpected_error}.