Code style fixes

Author: allflame

src/Log/AbstractLog.php

@@ -7,7 +7,7 @@ abstract class AbstractLog extends \Jaeger\Thrift\Log
 {
     public function __construct(array $tags = [], int $timestamp = 0)
     {
-        $this->timestamp = $timestamp ?? (int)round(microtime(true) * 1000000);
+        $this->timestamp = 0 !== $timestamp ? $timestamp : (int)round(microtime(true) * 1000000);
         $this->fields = $tags;
         parent::__construct();
     }