Improve interoperability with reactphp/promise

[samuelnogueira]

Q	A
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	fixes #30
License	MIT

What's in this PR?

$onFulfilled callables passed to Http\Adapter\React\Promise::then are no longer required to return the response.

Example Usage

/** @var \Http\Adapter\React\Client $client */
/** @var \Psr\Http\Message\RequestInterface $request */
$client->sendAsyncRequest($request)->then(function (\Psr\Http\Message\ResponseInterface $response) {
    echo $response->getBody();
});

[samuelnogueira]

Closed and re-opened PR to trigger rebuild in travis-ci

[dbu]

its green now!

i am not familiar enough with react to tell if there could be issues with this. @shulard and @joelwurtz wdyt?

[joelwurtz]

It's a little bit against the specification of async httplug , but okish

[dbu]

thanks @samuelnogueira !

It's a little bit against the specification of async httplug , but okish

i guess thats more a complaint about what react is doing than what we do here in the adapter? if react defines it like this, we have to work with it i guess...