I'm not sure where to start the initial issue/report ... well let's start
When creating the guzzle client or starting the request the verify option of guzzle gets ignored and not passed on. But this problems boils deep into the react library.
Here's the chain of objects / created instances
The HttpClientAdapter is creating an HttpClient based on React/Http/Client
The React\Http\Client is creating a React\SocketClient\SecureConnecter Object
The React\SocketClient\Connector Object is creating the initial stream object using stream_context_create() and stream_socket_client() with an empty stream_context array.
The solution would be that we would be able to push down additional stream_context options down the pipe to the React\SocketClient\Connector object .... then we could transport the given parameters down to the stream creating object.
In the meantime it looks like i'm not able to use the react-guzzle-psr7 package due to this problem where I'm not able to turn the verification on and off for testing.
You're in the right place but the main problem lies somewhere else. The connector object doesn't accept any context options so I can't implement that feature yet. There is however a PR on the matter that would resolve this issue: reactphp/socket-client#17