Adding success event when the putRecords call on kinesis returns data with no errors.

[menarguez]

PR Changes:

• Added unit tests
• Updated README.md
• Added success event trigger when the callback to putRecords returns with no errors, but valid data object

Description

This PR adds a success event that will be triggered on a successful write of putRecords if no errors were present

Testing

Unit tests, local testing.

• This change adds test coverage for new/changed/fixed functionality

const KinesisStream = require('./index');

const ks = new KinesisStream({
  // accessKeyId:     'KEY_ID',
  // secretAccessKey: 'SECRET_KEY',
  region:          'xxxx',
  streamName:      'xxxx',
  partitionKey:    'MyApp'
}).on('success', (records) => {
  console.log(records)
}).on('error', (err) => {
  console.log(err)
})

const sampleRecord = {'data': 'some data'}

ks.write(new Buffer.from(JSON.stringify(sampleRecord)))
ks.write(new Buffer.from(JSON.stringify(sampleRecord)))
ks.flush()

outputs

➜  kinesis-writable git:(Add-success-event) ✗ node michaelTest.js
{
  FailedRecordCount: 0,
  Records: [
    {
      SequenceNumber: '49611750915246315708736858648611579378510795612828467202',
      ShardId: 'shardId-000000000000'
    },
    {
      SequenceNumber: '49611750915246315708736858648612788304330410242003173378',
      ShardId: 'shardId-000000000000'
    }
  ]
}

Checklist

• I have added documentation for new/changed functionality in this PR or in auth0.com/docs
• All active GitHub checks for tests, formatting, and security are passing (There are some vulnerabilities proposed to be fixed in another PR
• The correct base branch is being used, if not master