Function FlashString

src/ArduinoJson/Strings/Adapters/FlashString.hpp:16–17

  static const size_t typeSortKey = 1;

  FlashString(const __FlashStringHelper* str, size_t sz)
      : str_(reinterpret_cast<const char*>(str)), size_(sz) {}

  bool isNull() const {
    return !str_;