Style fix

Author: trowski

src/Driver/Http1Driver.php

@@ -908,7 +908,7 @@ private function send(?Future $lastWrite, Response $response, ?Request $request
                 if ($chunk === "") {
                     continue;
                 }
-                $wrote += strlen($chunk);
+                $wrote += \strlen($chunk);
 
                 if ($chunked) {
                     $chunk = \sprintf("%x\r\n%s\r\n", \strlen($chunk), $chunk);

src/Driver/Http2Driver.php

@@ -348,7 +348,7 @@ private function send(int $id, Response $response, Request $request, Cancellatio
                 if (!isset($this->streams[$id])) {
                     return;
                 }
-                $wrote += strlen($chunk);
+                $wrote += \strlen($chunk);
 
                 $this->writeData($chunk, $id);