How to stream data in a serial mode?

[ababo]

When I create GCDWebServerStreamedResponse with asyncStreamBlock I end up with multiple threads simultaneously calling my handler. This is a bad scenario for me, since I want to process data and stream it sequentially (i.e. the order is important). This means I have to use NSLock or synchronise via single-threaded DispatchQueue which is far from an efficient implementation I would expect to achieve.

The ideal API would guarantee that my handler isn't called simultaneously in multiple threads. Alternatively I would like to use a synchronous streaming, when the request handler is called only once allowing me to call GCDWebServerBodyReaderCompletionBlock for multiple times, so I would call it in a loop while processing my data.

Can you clarify the way I should use GCDWebServer in my case?