std::string utf16ToUtf8(const StringPiece16& utf16) {
    ssize_t utf8Length = utf16_to_utf8_length(utf16.data(), utf16.length());
    if (utf8Length <= 0) {
        return {};
    }

    std::string utf8;
    utf8.resize(utf8Length);
    utf16_to_utf8(utf16.data(), utf16.length(), &*utf8.begin());
    return utf8;
}
StringPiece16 trimWhitespace(const StringPiece16& str) {
    if (str.size() == 0 || str.data() == nullptr) {
        return str;
    }

    const char16_t* start = str.data();
    const char16_t* end = str.data() + str.length();

    while (start != end && util::isspace16(*start)) {
        start++;
    }

    while (end != start && util::isspace16(*(end - 1))) {
        end--;
    }

    return StringPiece16(start, end - start);
}