title: How to ignore zero value in struct in Google Datastore for Golang?
body: <p>I am trying to use Google Datastore to store data by Go. Since the <code>EndDate</code> is optional field, and don't want to store zero value in that field. If I make a pointer for time field, Google Datastore will send an error message - <code>datastore: unsupported struct field type: *time.Time</code></p>
  
  <p>How can I ignore zero value field in struct?</p>
  
  <pre><code>type Event struct {
      StartDate time.Time `datastore:"start_date,noindex" json:"startDate"`
      EndDate   time.Time `datastore:"end_date,noindex" json:"endDate"`
  }
  </code></pre>