PSR风格

$bufferStream = new BufferStream();
$bufferStream->write(json_encode(['foo' => 'bar']));
$response = SaberGM::psr()
    ->withMethod('POST')
    ->withUri(new Uri('http://httpbin.org/post?foo=bar'))
    ->withQueryParams(['foo' => 'option is higher-level than uri'])
    ->withHeader('content-type', ContentType::JSON)
    ->withBody($bufferStream)
    ->exec()->recv();
echo $response->getBody();