Agora RTC Objective-C API Reference Refactor

### - f -

- FaceShapeAreaOptions() : FaceShapeAreaOptions
- FaceShapeBeautyOptions() : FaceShapeBeautyOptions
- fillAlphaData : AgoraVideoFrame
- fillVideoFrameData() : IVideoFrame
- fillVideoFrameMetaData() : IVideoFrame
- fireEvent() : IExtensionControl
- fireEvent:extension:key:value: : <AgoraExtControlDelegate>
- forceNextIntraFrame() : ILocalUser
- FreeIfNeeded() : OptionalBase< T >