title: AWS.DynamoDB.DocumentClient is not providing data on put
body: <p>I am using the AWS.DynamoDB.DocumentClient, with Dynamodb local (port 8080). When I perform a put, the <code>data</code> variable in the callback is an empty object. Have I missed something?</p>
  
  <pre><code>import * as AWS from "aws-sdk";
  
  
  AWS.config.update({
    region: "us-west-2",
    endpoint: "http://localhost:8080"
  });
  
  
  const docClient: any = new AWS.DynamoDB.DocumentClient();
  
  
  const item = {
        someField:    "456",
        other:         "123"
  };
  
  const params = {
    TableName: "TableName",
    Item: item
  };
  
  docClient.put(params, function(err, data) {
    if (err) console.log(err);
    else console.log(data); // this produces: {}
  });
  </code></pre>
  
  <p>There is no error, and the item is being inserted\updated - however the <code>data</code> variable is an empty object. Shouldn't this contain values?</p>
  
  <p>Thanks</p>