azure-storage-common/src/Common/Middlewares/MiddlewareStack.php
public function apply(callable $handler)
    {
        $result = $handler;
        foreach ($this->middlewares as $middleware) {
            $result = $middleware($result);
        }

        return $result;
    }
public function apply(callable $handler)
    {
        $result = $handler;
        foreach ($this->middlewares as $middleware) {
            $result = $middleware($result);
        }

        return $result;
    }
Apply the middlewares to the handler.

@param  callable $handler the handler to which the middleware applies.

@return callable