src/View/Helper/Alert.php
public function start($type = self::TYPE_INFO, array $options = array())
    {
        if ($this->captureLock) {
            throw new \RuntimeException('Cannot start capture, there is already a capture running.');
        }
        $this->captureLock    = true;
        $this->captureType    = $type;
        $this->captureOptions = $options;
        ob_start();

        return $this;
    }
public function start($type = self::TYPE_INFO, array $options = array())
    {
        if ($this->captureLock) {
            throw new \RuntimeException('Cannot start capture, there is already a capture running.');
        }
        $this->captureLock    = true;
        $this->captureType    = $type;
        $this->captureOptions = $options;
        ob_start();

        return $this;
    }
Starts content capturing.

@param string|array $type
@param array        $options see {@łink render()} for information.

@return self
@throws \RuntimeException if there's already another capturing process running.