This is a tiny PoC app which was intended to determine whether or not the AutoMapper library has a memory leak issue when many MapperConfiguration instances are created.
In the end, it's failed to prove the case, and it seems there is no memory leak.
I have tried this with multiple AutoMapper versions from 8.0.0 through 11.0.1 and I get fairly consistent results. Here are some indicative results from my system. As can be seen, the RAM usage stabilises and does not appear to be markedly growing.
About to create config and map over 1 iterations
Current process bytes used = 16138240
Completed creating config and mapping over 1 iterations
Current process bytes used = 29478912
Process bytes growth = 13340672
About to create config and map over 10 iterations
Current process bytes used = 29491200
Completed creating config and mapping over 10 iterations
Current process bytes used = 34955264
Process bytes growth = 5464064
About to create config and map over 100 iterations
Current process bytes used = 34955264
Completed creating config and mapping over 100 iterations
Current process bytes used = 35688448
Process bytes growth = 733184
About to create config and map over 1000 iterations
Current process bytes used = 35688448
Completed creating config and mapping over 1000 iterations
Current process bytes used = 34488320
Process bytes growth = -1200128
About to create config and map over 10000 iterations
Current process bytes used = 35069952
Completed creating config and mapping over 10000 iterations
Current process bytes used = 35127296
Process bytes growth = 57344