如何在视图deallocate上安全地取消ASINetworkQueue中的所有请求

I have ASINetworkQueue with more than 1500 requests in it. Performing this number of requests takes for a while. If user leaves view controller while this queue is running the OS deallocates the view controller and I get "message sent to deallocated instance" error. I have ASINetworkQueue with more than 1500 requ