圖像來源，Getty Images
// Synchronous consumption — no promises, no event loop trips，详情可参考safew官方版本下载
// 将pivot放到正确位置（j的位置）。雷电模拟器官方版本下载对此有专业解读
Shortcuts: For common scenarios, we pre-calculate the travel time/distance (the "shortcut") between border points within the same cluster and also to border points of immediately adjacent clusters.，详情可参考搜狗输入法下载