These only show up during unity builds, and they originate from
Boost.Container's small vector. The compiler's diagnostic also doesn't
make any sense here so it's probably just a weird GCC thing.
Events, parameter changes, and the individual queues contained within
the parameter changes all use dynamic memory allocation. Preallocating
some memory for those things inside of the objects may prevent latency
spikes when they those objects are first filled. This is especially
useful for the parameter changes since there's no way to reserve memory
in a vector of vectors.
Apparently this can actually make a difference in some cases, and the
C++ Core Guideliens recommend doing this on all default constructors,
destructors, and all functions that can not throw (and thus also don't
allocate).
Robbert van der Helm