如何在button按钮组件设置渐变的背景颜色

@Entry
@Component
struct Index {
  build() {
    Button('test')
      .width(200)
      .height(50)
      .backgroundColor('#00000000')
      .linearGradient({
        angle: 90,
        colors: [[0xff0000, 0.0], [0x0000ff, 0.3], [0xffff00, 1.0]]
      })
  }
}