message: telemetry_impl: remove atomic for structs
  The atomic calls for structs are not supported on iOS yet, so
  they are disabled for now and will need to be replaced with
  mutexes.
diff: @@ -28,9 +28,11 @@ private:
  // Use atomic to make this threadsafe
  std::atomic<float> _absolute_altitude;
  std::atomic<float> _relative_altitude;
  - std::atomic<Telemetry::Coordinates> _coordinates;
  + // TODO: make struct thread-safe
  + Telemetry::Coordinates _coordinates;
  std::atomic_bool _in_air;
  - std::atomic<Telemetry::Quaternion> _attitude_quaternion;
  + // TODO: make struct thread-safe
  + Telemetry::Quaternion _attitude_quaternion;
  };
  } // namespace dronelink
  