This is for structs that utilize over-allocation, either flexible array
members, or which store optional additional objects in the same allocation
block.
Rather than continuously wrapping when used, each update uses it from the front
and copies the tail to the front at the end. This allows for more effficient
accesses in loops.
This provides better characteristics for an amplitude limiter. In particular,
it utilizes the peak amplitude instead of the RMS, and the used parameters
basically guarantee no output samples exceed the given threshold... almost, due
to floating-point errors as the threshold is converted from dB to log-e for the
envelope, then is negated and converted to linear amplitude to apply to the
signal. It's quite possible for some rounding errors to creep in and not
perfectly saturate the result.
