framework/web/Response.php
public function setStatusCode($value, $text = null)
    {
        if ($value === null) {
            $value = 200;
        }
        $this->_statusCode = (int) $value;
        if ($this->getIsInvalid()) {
            throw new InvalidArgumentException("The HTTP status code is invalid: $value");
        }
        if ($text === null) {
            $this->statusText = isset(static::$httpStatuses[$this->_statusCode]) ? static::$httpStatuses[$this->_statusCode] : '';
        } else {
            $this->statusText = $text;
        }

        return $this;
    }
public function setStatusCode($value, $text = null)
    {
        if ($value === null) {
            $value = 200;
        }
        $this->_statusCode = (int) $value;
        if ($this->getIsInvalid()) {
            throw new InvalidArgumentException("The HTTP status code is invalid: $value");
        }
        if ($text === null) {
            $this->statusText = isset(static::$httpStatuses[$this->_statusCode]) ? static::$httpStatuses[$this->_statusCode] : '';
        } else {
            $this->statusText = $text;
        }

        return $this;
    }
Sets the response status code.
This method will set the corresponding status text if `$text` is null.
@param int $value the status code
@param string $text the status text. If not set, it will be set automatically based on the status code.
@throws InvalidArgumentException if the status code is invalid.
@return $this the response object itself