code: func BGRA(p []uint8) {
  	for i := 0; i < len(p); i += 4 {
  		p[i+0], p[i+2] = p[i+2], p[i+0]
  	}
  }
docs: // BGRA converts BGRA array of pixels to RGBA
  // https://github.com/golang/exp/blob/master/shiny/driver/internal/swizzle/swizzle_common.go#L13