effSetSpeakerArrangement return code does not seem to make sense

Which means that it might well say "no" everytime as of today. Whereas in Iplug it says always "yes".
However this has the potential to break lots of compatibility, so let's be extra-careful here

(EDIT: actually in Audio Unit, we also say "no" everytime for speaker arrangement, so maybe there is this logic of not pretending to support it)

The issue names effSetSpeakerArrangement but does not identify a file or test; start by locating that entry point and comparing its return behavior with the Iplug and Audio Unit cases mentioned. Confirm the intended compatibility semantics before changing anything; done requires a decided behavior with coverage demonstrating it.

Written by the indexing model from the issue text.