Character encoding while logging custom log format in access log

I am using squid 4.0.21 with ecap version 1.0
I used to a custom access log format:
logformat customLogFormat %ts.%03tu %6tr %>a %ru %{status_info}adapt::<last_h

# TAG: access_log
access_log daemon:/usr/local/squid/var/logs/access.custom.log customLogFormat

ecap code for log the field %{status_info}adapt::<last_h is follows

string statusData;

/**
 *
 * @param visitor
 */
void RequestAction::visitEachOption(libecap::NamedValueVisitor &visitor) const {

    if(!statusData.empty()){
        visitor.visit(loggingStatus, Area(statusData.data(), statusData.size()));
    }
}
.
.
.
.

void RequestAction::start()
{
      /*
     some codes here
     */
                 statusData="12\\33\\testing";

                //pass the request as such.
  hostx->useVirgin();

}

But the squid access log is logged statusData as 12%5C33%5Ctesting instead of 12\33\testing
Squid logs the character '\' as %5C in access log. I need to log the filed %{status_info}adapt::<last_h as 12\33\testing

Could any one please help to resolve the issue