public function extractOverflow() {
        if ($this->isCoalesced()) {
            $endPoint  = $this->getPayloadLength();
            $endPoint += $this->getPayloadStartingByte();

            if ($this->bytesRecvd > $endPoint) {
                $overflow   = substr($this->data, $endPoint);
                $this->data = substr($this->data, 0, $endPoint);

                return $overflow;
            }
        }

        return '';
    }