in core/src/main/scala/com/gu/marley/AvroSerialisable.scala [79:84]
override def writableValue(t: scala.collection.Set[T]): Any = t.map(w.writableValue).asJava
override def read(x: Any): collection.Set[T] = x.asInstanceOf[java.util.List[Any]].asScala.map(w.read).toSet
}
def MapAvroSerialisable[V](wv: AvroSerialisable[V]) =
new AvroSerialisable[collection.Map[String,V]] {