FString转UTF8
FString szMsg = "test msg";
TCHAR* pSendData = szMsg.GetCharArray().GetData();
int32 nDataLen = FCString::Strlen(pSendData);
uint8* dst = (uint8*)TCHAR_TO_UTF8(pSendData);
UTF8转FString
TArray<uint8> receiveBuff;
RecvData(receiveBuff, buffLen));
receiveBuff.Add('\0');
FString str = FString(reinterpret_cast<const char*>(receiveBuff.GetData()));