UE5 - delegates in c++ - EOS Subsystem

I don’t know what to pass in for the OnDone variable in the following example

void UOnlineGameInstanceSubsystem::StartCreateSession(
const UObject* WorldContextObject,
int32 Slots,
bool bIsLan,
FString MatchType,
FOnlineSubsystemCreateSessionComplete OnDone)

The delegate is declared as

DECLARE_DYNAMIC_DELEGATE_OneParam(FOnlineSubsystemCreateSessionComplete, bool, WasSuccessful);

Any help would be gratefully appreciated.
Thanks.