Custom llm driver

<?php
require 'examples/boot.php';

use Cognesy\Config\Env;
use Cognesy\Http\Data\HttpRequest;
use Cognesy\Http\Data\HttpResponse;
use Cognesy\Messages\Messages;
use Cognesy\Polyglot\Inference\Config\LLMConfig;
use Cognesy\Polyglot\Inference\Creation\BundledInferenceDrivers;
use Cognesy\Polyglot\Inference\Drivers\OpenAI\OpenAIDriver;
use Cognesy\Polyglot\Inference\Inference;
use Cognesy\Polyglot\Inference\InferenceRuntime;
use Cognesy\Utils\Str;

// we will use existing, bundled driver as an example, but you can provide any class that implements
// the inference driver contract and inject it into a runtime-local registry

$drivers = BundledInferenceDrivers::registry()->withDriver(
    name: 'custom-driver',
    driver: fn ($config, $httpClient, $events) => new class($config, $httpClient, $events) extends OpenAIDriver
    {
        #[\Override]
        protected function makeHttpResponse(HttpRequest $request): HttpResponse
        {
            // some extra functionality to demonstrate our driver is being used
            echo ">>> Handling request...\n";

            return parent::makeHttpResponse($request);
        }
    },
);

// Create instance of LLM client initialized with custom parameters
$config = new LLMConfig(
    apiUrl          : 'https://api.openai.com/v1',
    apiKey          : (string) Env::get('OPENAI_API_KEY', ''),
    endpoint        : '/chat/completions', model: 'gpt-4o-mini', maxTokens: 128,
    driver          : 'custom-driver',
);

$answer = Inference::fromRuntime(InferenceRuntime::fromConfig($config, drivers: $drivers))
    ->withMessages(Messages::fromString('What is the capital of France'))
    ->withOptions(['max_tokens' => 64])
    ->get();

echo "USER: What is capital of France\n";
echo "ASSISTANT: $answer\n";

assert(Str::contains($answer, 'Paris'));
?>