src/Server.php
public function listen(callable $finalHandler = null)
    {
        $callback = $this->callback;

        ob_start();
        $bufferLevel = ob_get_level();

        $response = $callback($this->request, $this->response, $finalHandler);
        if (! $response instanceof ResponseInterface) {
            $response = $this->response;
        }
        $this->getEmitter()->emit($response, $bufferLevel);
    }
public function listen(callable $finalHandler = null)
    {
        $callback = $this->callback;

        ob_start();
        $bufferLevel = ob_get_level();

        $response = $callback($this->request, $this->response, $finalHandler);
        if (! $response instanceof ResponseInterface) {
            $response = $this->response;
        }
        $this->getEmitter()->emit($response, $bufferLevel);
    }
public function listen ( callable $ finalHandler = null ) { $ callback = $ this -> callback ; ob_start ( ) ; $ bufferLevel = ob_get_level ( ) ; $ response = $ callback ( $ this -> request , $ this -> response , $ finalHandler ) ; if ( ! $ response instanceof ResponseInterface ) { $ response = $ this -> response ; } $ this -> getEmitter ( ) -> emit ( $ response , $ bufferLevel ) ; }
"Listen" to an incoming request

If provided a $finalHandler, that callable will be used for
incomplete requests.

Output buffering is enabled prior to invoking the attached
callback; any output buffered will be sent prior to any
response body content.

@param null|callable $finalHandler
Listen to an incoming request