文件位置：
cartographer/mapping/internal/2d/scan_matching/real_time_correlative_scan_matcher_2d.cc
cartographer/mapping/internal/2d/scan_matching/correlative_scan_matcher_2d.h
cartographer/mapping/internal/2d/scan_matching/real_time_correlative_scan_matcher_2d.h
RealTimeCorrelativeScanMatcher2D::GenerateExhaustiveSearchCandidates
生成備選位姿
RealTimeCorrelativeScanMatcher2D::ScoreCandidates
爲每一種備選位姿計算權重
RealTimeCorrelativeScanMatcher2D::Match
最終擇優匹配