Return value of `pstream-play` doesn't match documentation

[soegaard]

A call to pstream-play returns "sound is queued", but the documentation says that the pstream is to be returned.

[cwebber]

It looks like this happened quite a while ago, in commit 41fd2b34e862bc3602d09d62fdfe380201d11260

But I wonder why? I imagine one of two things:

• either this was a debugging commit that never got reverted
• or pstream changed from a "functional stream" conception to just an imperative "audio streaming" interface

If it's the latter though, I don't understand why this wouldn't just return void?