Updated readme

Author: jrabausch

README.md

@@ -3,7 +3,7 @@
 <img src="https://avatars0.githubusercontent.com/u/76976189?s=140" alt="Semperton">
 </a>
 <h1>Semperton Proxy</h1>
-<p>Simple PHP proxy.</p>
+<p>Simple PSR-18 HTTP client based on PHP's native stream socket.</p>
 //
 </div>
 
@@ -17,3 +17,36 @@ Just use Composer:
 composer require semperton/proxy
 ```
 Proxy requires PHP 7.1+
+
+## Usage
+The client does not come with a PSR-17 request/response factory by itself.
+You have to provide one in the constructor.
+
+```php
+use HttpSoft\Message\ResponseFactory;
+use Semperton\Proxy\Client;
+
+$client new Client(
+	new ResponseFactory(), // any PSR-17 compilant response factory
+	5, // request timeout in secs
+	$options, // array of stream context options
+	4096 // buffer size used to read/write request body
+);
+```
+
+The client exposes only one public method ```sendRequest```:
+```php
+use HttpSoft\Message\RequestFactory;
+use Psr\Http\Message\ResponseInterface;
+
+$requestFactory = new RequestFactory();
+$request = $requestFactory->createRequest('GET', 'https://google.com');
+
+$response = $client->sendRequest($request);
+
+$response instanceof ResponseInterface // true
+
+```
+
+## Note
+This is just a very simple HTTP client for single requests. If you are going to do heavy API work (multiple asynchronous requests, body parsing, etc.), you should consider using ```guzzlehttp/guzzle``` or ```symfony/http-client```.