What problem does this feature solve?

i want to set loading custom indicator do not use default setting. default support

default: {
  text: 'loading',
  color: '#c23531',
  textColor: '#000',
  maskColor: 'rgba(255, 255, 255, 0.8)',
  zlevel: 0,
  fontSize: 12,
  showSpinner: true,
  spinnerRadius: 10,

  lineWidth: 5,

  fontWeight: 'normal',

  fontStyle: 'normal',
  
  fontFamily: 'sans-serif'
}

echart version 5.2.2
but not support set custom indicator i want to use css background-url

What does the proposed API look like?

myChart.showLoading({
      text: "",
      backgroundColor: "red",
      backgroundImage: "url(xxxx.png)",
      backgroundSize: "50px",
    });