src/Leevel/Protocol/Pool.php
public function pool(string $className): SplStack
    {
        $this->valid($className);
        $className = $this->normalize($className);
        $pool = $this->pools[$className] ?? null;

        if (null !== $pool) {
            return $pool;
        }

        return $this->pools[$className] = new SplStack();
    }
public function pool(string $className): SplStack
    {
        $this->valid($className);
        $className = $this->normalize($className);
        $pool = $this->pools[$className] ?? null;

        if (null !== $pool) {
            return $pool;
        }

        return $this->pools[$className] = new SplStack();
    }
获取对象栈.

@param string $className

@return \SplStack