How to see Debug logging in firebase?

问题

I am using firebase version 11.0.1

I try this code

FirebaseDatabase.getInstance().setLogLevel(Logger.Level.DEBUG);

but it doesn't work! syntax error.. I click on level class and this is what I see??? package com.google.firebase.database;

public interface Logger {
    public static enum Level {
        zzbYY,
        zzbYZ,
        zzbZa,
        zzbZb,
        zzbZc;

        private Level() {
        }
    }
}

Is deprecated? How to do it?

来源：https://stackoverflow.com/questions/44767654/how-to-see-debug-logging-in-firebase