Ok man the docs are fuzzy on this but I found the answer. You need const like so:
UFUNCTION(NetMulticast, Reliable, WithValidation) void playerJoined(const FString& playerNamesSent);
Ok man the docs are fuzzy on this but I found the answer. You need const like so:
UFUNCTION(NetMulticast, Reliable, WithValidation) void playerJoined(const FString& playerNamesSent);