sum of dynamic memory usage of all the map elements (NOT the maps themselves)
Declared in <txmempool.h>
[[guarded_by(0x7fb95f554998), guarded_by(0x7fb968bc60a8), guarded_by(0x7fb95fdcfee8), guarded_by(0x7fb978b752a8), guarded_by(0x7fb96b8fa808), guarded_by(0x7fb96e5c12d8), guarded_by(0x7fb97a07b308), guarded_by(0x7fb96be43058)]]
uint64_t cachedInnerUsage = {0};