rem: virtual void buffersize(long int samples, long int sample_rate) { child_repp->buffersize(samples, sample_rate); }
add: virtual long int buffersize(void) const { return(child_repp->buffersize()); }
context:   virtual void buffersize(long int samples, long int sample_rate) { child_repp->buffersize(samples, sample_rate); }