#### Setting headers on messages

Messages sent over the event bus can also contain headers.

This can be specified by providing a `headers` object inside the `DeliveryOptions` object when sending or publishing:

    options = {
     headers: {
       'some-header' => 'some-value'
     }
    }
    vertx.event_bus().send("news.uk.sport", "Yay! Someone kicked a ball", options)

On the other side, the consumer can retrieve the message header as follows:

    eb = $vertx.event_bus()
    eb.consumer("news.uk.sport") { |message|
     puts message.headers().get("some-header")
    }