trailer headers for stream responses

[weierophinney]

My php service generates a very big list of items.
I decided to stream items on the fly as they are generated to save memory.
I implemented response body as a custom stream that wraps a generator which yields items.

Now I need to append a checksum trailer header to that stream response, so clients can check response validity.

What is a proper way of appending trailer header to a stream response in diactoros?

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Originally posted by @drscre at zendframework/zend-diactoros#231