OSD 一直不识别是为什么呢？不会进入事件，addOSDMarker 返回的也是null

我用uniapp开发的，全部代码如下。不会进入事件

<script setup lang="ts">
import {onLoad} from "@dcloudio/uni-app";

let session :any= null
let markerId :any= null

onLoad((op:any)=>{
    // @ts-ignore
    const version = wx.getAppBaseInfo().SDKVersion
    console.log("url",version,op.url)
    // @ts-ignore
    session = wx.createVKSession({
        track: {
            OSD: true,
        }
    })
    addOSDMarker(op.url);
})

function startOSD(){
    session.start((err:any)=>{
        console.log("start err",err)
        session.on("addAnchors",(anchors :any[])=>{
            console.log("addAnchors",anchors)
        })
        session.on("updateAnchors",(anchors :any[])=>{
            console.log("updateAnchors",anchors)
        })
        session.on("removeAnchors",(anchors :any[])=>{
            console.log("removeAnchors",anchors)
        })
    })

}
function addOSDMarker(url:string) {
    // @ts-ignore
    const path = `${wx.env.USER_DATA_PATH}/find_osd_obj.jpg`
    // @ts-ignore
    wx.downloadFile({
        url: url,
        filePath:path,
        success: (obj:any) => {
            console.log("downloadFile success",obj)
            markerId = session.addOSDMarker(obj.filePath)
            console.log('addOSDMarker', markerId)
            startOSD()
        }
    })
}
function btnTest(){
    console.log("getAllOSDMarker",session.getAllOSDMarker())

}
</script>

<template>
    <camera type="webgl" style="width: 100%; height: 70vh;">
    </camera>
    <button @click="btnTest">测试</button>
</template>

<style scoped lang="scss">

</style>

Start with the inline uni-app TypeScript example, especially the onLoad handler, wx.createVKSession setup, addOSDMarker call, and startOSD event registration. Reproduce the reported null marker ID and missing anchor events, then consult the relevant API behavior and document a confirmed cause or correction for this example.