PFNGLTEXTURESUBIMAGE2DEXTPROCDart typedef
        PFNGLTEXTURESUBIMAGE2DEXTPROCDart =
     void Function(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, Pointer<NativeType>  pixels)
    
    
    
Implementation
typedef PFNGLTEXTURESUBIMAGE2DEXTPROCDart =
    void Function(
      int texture,
      int target,
      int level,
      int xoffset,
      int yoffset,
      int width,
      int height,
      int format,
      int type,
      Pointer<NativeType> pixels,
    );