code: public MessageRequest withContext(java.util.Map<String, String> context) {
          setContext(context);
          return this;
      }
docs: A map of custom attributes to attributes to be attached to the message. This payload is added to the push
  notification's 'data.pinpoint' object or added to the email/sms delivery receipt event attributes.
  
  @param context
  A map of custom attributes to attributes to be attached to the message. This payload is added to the push
  notification's 'data.pinpoint' object or added to the email/sms delivery receipt event attributes.
  @return Returns a reference to this object so that method calls can be chained together.