Kafka structured straming - how to read headers

[eugen . wintersberger]

Hi folks,
  I am trying to read the message headers from a Kafka structured
stream which should be stored in a column named ``headers``. 
I try something like this:

val stream = sparkSession.readStream.format("kafka")......load()
stream.map(row => { 
 ...
 val headers = row.getAs[HeaderT]("headers")
....
})

My question is: what would be HeaderT?

Thanks in advance

 Eugen