feat:设置读取杠杆，能缓存杠杆

@@ -42,6 +42,7 @@ class CmBroker
     /** @var Pos[] $positions */
     public $positions = [];
     public $name = '';
+    public $levers = [];
 
 
     public function __construct($plat, ApiInfo $apiInfo)
@@ -248,13 +249,17 @@ class CmBroker
             }
             $levers = $resNew;
         }
+        $this->levers = $levers; //缓存levers
         return $levers;
     }
     //设置杠杆
     public function setLever($symbol, $lever)
     {
         $symbol = $this->getSymbolOri($symbol, $this->plat);
-        $this->exBroker->setLever($symbol, $lever);
+        $res = $this->exBroker->setLever($symbol, $lever);
+        if ($res) {
+            $this->levers[$symbol] = $lever;
+        }
     }
     //查询获取全部持仓
     public function getAllPos(): array