Experimental Physics and
Industrial Control System

Only shortcoming would be that 'info' operations hands you an empty container.
So instead of for example
   StructureDescriptor "timeStamp": { LongDescriptor "secondsPastEpoch", IntDescriptor "nanoseconds", ... }
you get a
   PVAStructure "timeStamp": { PVALong "secondsPastEpoch" = 0, PVAInt "nanoseconds" = 0, ... }
The caller of PVAChannel.info() needs to know that the obtained PVAStructure is empty, it's only meant to describe the data.
Nothing keeps you from printing the timestamp with secondsPastEpoch, nanoseconds, .. and then you see that all values are 0, NaN, [].
Yes, that means inside the client you now have a PVALong with 8 wasted bytes for the long value = 0, a PVAInt with 4 wasted bytes for the int value = 0.
But in the bigger picture, those long, int, double values don't waste much space.
Would be bad if fetching the info for an NTNDArray got the actual int[2,000,000] data array, but all you get is int[0].

-- 
Complexity comes for free, Simplicity you have to work for.