var buf:Buffer = GL.allocBuffer(GL.FLOAT, 10);
buf[0] = 0; // set first float to 0
buf[1] = 2; // set second float to 2

var fbuf:FloatBuffer = buf;
fbuf[0] = 0; // set first float to 0, but faster
fbuf[1] = 2; // set second float to 2, but faster

The Buffer array access functions have to check the GL type of the buffer to see what functions to use
Casting to FloatBuffer (checked cast) permits faster access :)