将应用程序从Angular 5迁移到Angular 6时会出现错误，
Module '/node_modules/rxjs/observable/TimerObservable' has no exported member 'TimerObservable'.
码：
import { Injectable } from '@angular/core';
import { TimerObservable } from 'rxjs/observable/TimerObservable';
import { Observable } from 'rxjs';
@Injectable()
export class TimerTestScv {
static fetchTimer(interval: number, initialDelay: number): Observable<number>
{
return TimerObservable.create(initialDelay, interval);
}
}
使用的rxjs包：
"rxjs": "^6.2.2",