Implement IAudioProcessor::setBusArrangements()

src/common/serialization/vst3/base.h

@@ -39,6 +39,11 @@ using ArrayUID = std::array<
     std::remove_reference_t<decltype(std::declval<Steinberg::TUID>()[0])>,
     std::extent_v<Steinberg::TUID>>;
 
+/**
+ * The maximum number of speakers or busses we support.
+ */
+constexpr size_t max_num_speakers = 16384;
+
 /**
  * The maximum size for an `IBStream` we can serialize. Allows for up to 50 MB
  * of preset data. Hopefully no plugin will come anywhere near this limit, but