==== 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 `link:../../vertx-core/dataobjects.html#DeliveryOptions[DeliveryOptions]` object when sending or publishing:

[source,ruby]
----
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:

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