hippy现在还不支持fixed定位， 请问现在怎么处理fixed定位的case

[durio61]

Describe the bug A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior A clear and concise description of what you expected to happen.

Screenshots If applicable, add screenshots to help explain your problem.

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS and version: [e.g. iOS 13.3.1]
• Hippy native SDK version: [e.g. 2.0.0]
• Front-end SDK and version [e.g. @hippy/vue 2.0.1]

Additional context Add any other context about the problem here.