src/ThrottleTrait.php
protected function _setIdentifier($request)
    {
        $key = $this->getConfig('identifier');
        if (!is_callable($this->getConfig('identifier'))) {
            throw new \InvalidArgumentException('Throttle identifier option must be a callable');
        }
        $this->_identifier = $key($request);
    }
protected function _setIdentifier($request)
    {
        $key = $this->getConfig('identifier');
        if (!is_callable($this->getConfig('identifier'))) {
            throw new \InvalidArgumentException('Throttle identifier option must be a callable');
        }
        $this->_identifier = $key($request);
    }
protected function _setIdentifier ( $ request ) { $ key = $ this -> getConfig ( 'identifier' ) ; if ( ! is_callable ( $ this -> getConfig ( 'identifier' ) ) ) { throw new \ InvalidArgumentException ( 'Throttle identifier option must be a callable' ) ; } $ this -> _identifier = $ key ( $ request ) ; }
Sets the identifier class property. Uses Throttle default IP address
based identifier unless a callable alternative is passed.

@param \Psr\Http\Message\ServerRequestInterface|\Cake\Http\Request $request RequestInterface instance
@return void
@throws \InvalidArgumentException
Sets the identifier class property . Uses Throttle default IP address based identifier unless a callable alternative is passed .