Update Client.php

In this section:

        } catch (\Exception $e) {
            throw RequestException::wrapException($trans->request, $e);
        }

Inspection return: 'void' method 'send' result used. Missing 'void' in PHPDocBlock comment (that solve this warning).

if ($request->getConfig()->get('future')) is false, and try { $fn($trans); } throw an Exception nothing is returned.

May be this is only a highlight syntax warning of IDE ...?