调用wx.createOffscreenCanvas()，在开发工具中编译通过，且能正常运行，但是在真机调试时总是报错，错误信息如下：

[publib]:1 appServiceSDKScriptError

Pr.default.OffscreenCanvas is not a constructor; at wx.createOffscreenCanvas

TypeError: Pr.default.OffscreenCanvas is not a constructor

    at [publib]:1:427374

    at Object.eo ([publib]:1:427410)

    at Object.<anonymous> ([publib]:1:247770)

    at Function.<anonymous> ([publib]:1:799299)

    at Object.<anonymous> ([publib]:1:234003)

    at test1 (weapp:///pages/heatmap/index.js:115:23)

    at H.onReady (weapp:///pages/heatmap/index.js:40:17)

    at H.<anonymous> ([publib]:1:1030813)

    at H.p.__callPageLifeTime__ ([publib]:1:1030572)

    at [publib]:1:1050566