void HeaderString::setReference(const std::string& ref_value) {
  freeDynamic();
  type_ = Type::Reference;
  buffer_.ref_ = ref_value.c_str();
  string_length_ = ref_value.size();
  ASSERT(valid());
}
void HeaderString::setReference(const std::string& ref_value) {
  freeDynamic();
  type_ = Type::Reference;
  buffer_.ref_ = ref_value.c_str();
  string_length_ = ref_value.size();
  ASSERT(valid());
}