sum of dynamic memory usage of all the map elements (NOT the maps themselves)
Declared in <txmempool.h>
[[guarded_by(0x7f2e1b5a0e68), guarded_by(0x7f2e27219e78), guarded_by(0x7f2e421cb588), guarded_by(0x7f2e2880a548), guarded_by(0x7f2e3212d8d8), guarded_by(0x7f2e347f5f68), guarded_by(0x7f2e2b05a3d8), guarded_by(0x7f2e2bee1a78)]]
uint64_t cachedInnerUsage = {0};