Method operator()

internal/message_equality.cc:275–278

struct MessageEqualer {
  bool operator()(EquatableMessage lhs, EquatableMessage rhs) const {
    return lhs.get().GetDescriptor() == rhs.get().GetDescriptor() &&
           MessageDifferencer::Equals(lhs.get(), rhs.get());
  }

  template <typename T>
  std::enable_if_t<std::negation_v<std::is_same<EquatableMessage, T>>, bool>