PFNGLCOPYTEXTURESUBIMAGE1DPROCDart typedef
        PFNGLCOPYTEXTURESUBIMAGE1DPROCDart =
     void Function(int texture, int level, int xoffset, int x, int y, int width)
    
    
    
Implementation
typedef PFNGLCOPYTEXTURESUBIMAGE1DPROCDart =
    void Function(int texture, int level, int xoffset, int x, int y, int width);