publish.js

var avroSchema = {
    type: 'record',
    name: 'MyClass',
    namespace: 'com.test.avro',
    fields: [
        {
        name: 'anonymousId',
        type: 'string'
    }, 
    {
        name: 'channel',
        type: 'string'
    }, 
    {
        name: 'ip',
        type: 'string'
    }, 
    {
        name: 'userAgent',
        type: 'string'
    }, {
        name: 'name',
        type: 'string'
    }, {
        name: 'email',
        type: 'string'
    }, {
        name: 'messageId',
        type: 'string'
    }, {
        name: 'receivedAt',
        type: 'string'
    }, {
        name: 'sentAt',
        type: 'string'
    }, {
        name: 'timestamp',
        type: 'string'
    }, {
        name: 'pageName',
        type: 'string'
    }, {
        name: 'title',
        type: 'string'
    }, {
        name: 'event',
        type: 'string'
    }, {
        name: 'userId',
        type: 'string'
    }, {
        name: 'version',
        type: 'string'
    }, {
        name: 'apiKey',
        type: 'string'
    }, {
        name: 'destinationBQ',
        type: 'string'
    }]
}; 

var obj = {
     anonymousId: "507f191e810c19729de860ea",
     channel: "browser",
     ip: "8.8.8.8",
     userAgent: "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.115 Safari/537.36",
     name: "Peter Gibbons",
     email: "peter@initech.com",
     messageId: "022bb90c-bbac-11e4-8dfc-aa07a5b093db",
     receivedAt: "2015-02-23T22:28:55.387Z",
     sentAt: "current time",
     timestamp: "India",
     pageName: "Home Page",
     title: "Analytics Academy",
     event: "Course Clicked",
     userId: "97980cfea0067",
     version: "1.1",
     apiKey: "jkhdhjasfgyugwqyewytyiuuiegwyhds",
     destinationBQ: "projectName:dataset.tableName"
   }

pubsubClient
        .topic(topicName)
        .publisher()
        .publish(Buffer.from(JSON.stringify(avroSchema)),obj)
        .then(results => {
            console.log(results);
            return results;
        })
        .catch(err => {
            console.error('ERROR:', err);
        });