Method timevalToString

src/thundersvm/util/log.cpp:1106–1115

            }

            std::string DateTime::timevalToString(struct timeval tval, const char* format,
                                                  const el::base::SubsecondPrecision* ssPrec) {
                struct ::tm timeInfo;
                buildTimeInfo(&tval, &timeInfo);
                const int kBuffSize = 30;
                char buff_[kBuffSize] = "";
                parseFormat(buff_, kBuffSize, format, &timeInfo, static_cast<std::size_t>(tval.tv_usec / ssPrec->m_offset),
                            ssPrec);
                return std::string(buff_);
            }

            base::type::string_t DateTime::formatTime(unsigned long long time, base::TimestampUnit timestampUnit) {
                base::type::EnumType start = static_cast<base::type::EnumType>(timestampUnit);