wx.startLocationUpdateBackground配合wx.onLocationChange接口使用，测试发现小程序至于后台后，无法收到位置变化通知。以下是错误信息：

onLocationChangeError {type: "string", description: "onLocationChangeError", value: "onLocationChangeError"} [object Object] {type: "object", description: "[object Object]", objectId: "74", className: "Object", preview: {type: "object", description: "[object Object]", properties: [{name: "errStr", type: "string", description: "ERROR_NOCELL&WIFI_LOCATIONSWITCHOFF", value: "ERROR_NOCELL&WIFI_LOCATIONSWITCHOFF"}, {name: "errCode", type: "number", description: "2", value: 2}], overflow: true}}

代码片段：https://developers.weixin.qq.com/s/V8ftqYmV79Kk