HTTP Client beforeSending does not take callables

[MariusSpring]

• Laravel Version: 8.7
• PHP Version: 8.1
• Database Driver & Version: 5.7

Description:

The beforeSending method on the PendingRequest class says that it takes a callable $callback, however, this is not entirely true. When the callback is called, it is done so using $callback->__invoke(...) and not $callback(...). This makes the following syntax result in error "Call to a member function __invoke() on array":

protected function buildRequest(): PendingRequest
{
    return Http::baseUrl('https://api.example.org')
        ->beforeSending([ $this, 'prepareRequest' ])
        ->asJson()
        ->withoutVerifying();
}

protected function prepareRequest(Request $request, array $options, PendingRequest $pendingRequest)
{
    $headers = [
        'X-Test-A' => 'test',
        'X-Test-B' => 'test',
        'X-Test-C' => 'test',
    ];

    $pendingRequest->withHeaders($headers);
}

I expect the code above to execute the prepareRequest method as the callable with the params passed. This happens if the callback would be called using $callback(...).

Steps To Reproduce:

1. Create a PendingRequest using Http fascade.
2. Set beforeSending to a callable referencing method on object using array syntax as demonstrated in description example,
3. Send request.
4. See error.

[driesvints]

Thanks, I've sent in a PR for this: #41489