public function computeTTL($ttl = null)
    {
        $ttl = $ttl ?: $this->defaultTTL;
        if ($ttl === null) {
            return null;
        }
        return $ttl + rand(0, $this->ttlVariation);
    }
public function computeTTL($ttl = null)
    {
        $ttl = $ttl ?: $this->defaultTTL;
        if ($ttl === null) {
            return null;
        }
        return $ttl + rand(0, $this->ttlVariation);
    }
public function computeTTL ( $ ttl = null ) { $ ttl = $ ttl ? : $ this -> defaultTTL ; if ( $ ttl === null ) { return null ; } return $ ttl + rand ( 0 , $ this -> ttlVariation ) ; }
Computes the final TTL taking into account the default ttl
and the ttl variation

@param int $ttl
@return int
Computes the final TTL taking into account the default ttl and the ttl variation