message: gapi(build): eliminate Win32 build warning
diff: @@ -109,7 +109,7 @@ public:
  : m_synced_frame_time;
  auto n_frames = p.end_time / frame_time;
  GAPI_Assert(n_frames > 0u);
  - return n_frames;
  + return (std::size_t)n_frames;
  }
  };
  