Performance improvements

[abumq]

1

Writer& Writer::construct(int count, const char* loggerIds, ...) {
  if (ELPP->hasFlag(LoggingFlag::MultiLoggerSupport)) {
    va_list loggersList;
    va_start(loggersList, loggerIds);
    const char* id = loggerIds;
    for (int i = 0; i < count; ++i) {
      m_loggerIds.push_back(std::string(id));

We can reserve space before pushing to speed up things. So just after const char* id = loggerIds; add m_loggerIds.reserve(count);

2

Provide interface for reserving space for custom format specifier so last line in this snippet could be sped up

void Storage::installCustomFormatSpecifier(const CustomFormatSpecifier& customFormatSpecifier) {
  if (hasCustomFormatSpecifier(customFormatSpecifier.formatSpecifier())) {
    return;
  }
  base::threading::ScopedLock scopedLock(lock());
  m_customFormatSpecifiers.push_back(customFormatSpecifier);