message: Guard stringification inspector against null
diff: @@ -81,13 +81,16 @@ public:
  }
  inline void consume(const char* cstr) {
  + if (cstr == nullptr) {
  + result_ += "null";
  + } else {
  string_view tmp{cstr, strlen(cstr)};
  consume(tmp);
  }
  + }
  inline void consume(char* cstr) {
  - string_view tmp{cstr, strlen(cstr)};
  - consume(tmp);
  + consume(const_cast<const char*>(cstr));
  }
  template <class T>
  