This counts how many multi-fragment user messages this device successfully reassembled back into complete messages, the receive-side complement to cSctpStatFragmentedUsrMessages on the sending peer. Comparing this against how many messages were originally fragmented by the sender helps confirm fragments are consistently arriving and being reassembled rather than getting lost and forcing message retransmission. A device where this count grows much slower than the corresponding fragmentation count on its peers suggests reassembly is failing for some fragments, likely due to loss of individual pieces on the path.