helperSubmit 传递堆内存有问题，传进去栈内存可以

rt,待调查
如下，在回调时可以在prefetchHandleReply传回来

char buf[4096];
snprintf(buf, 4096, "%s\n", (char*)(req_param->urls).items[0]);
helperSubmit(prefetchers, buf, prefetchHandleReply, state);

如下却存在问题

typedef struct _request_param
{
        Array urls;
}request_param;
helperSubmit(prefetchers, (char*)(req_param->urls).items[0], prefetchHandleReply, state);