PFNGLMULTITEXGENDVEXTPROCDart typedef
        PFNGLMULTITEXGENDVEXTPROCDart =
     void Function(int texunit, int coord, int pname, Pointer<Double>  params)
    
    
    
Implementation
typedef PFNGLMULTITEXGENDVEXTPROCDart =
    void Function(int texunit, int coord, int pname, Pointer<Double> params);