SnapKit源码分析Snapkit版本：5.6.01.给谁做约束ConstraintView：对iOS而言是UIView，对macOS而言是NSView#ifos(iOS)||os(tvOS)publictypealiasConstraintView=UIView#elsepublictypealiasConstraintView=NSView#endif给ConstraintView扩展了snp属性，snp为ConstraintViewDSL结构体publicextensionConstraintView{varsnp:ConstraintViewDSL{returnConstraintV
