==== prefetch_descriptor

Defined by DVB in <<ETSI-101-812>>.
Must be in an AIT (table id 0x74).

[source,xml]
----
<prefetch_descriptor transport_protocol_label="uint8, required">
  <!-- One per module -->
  <module label="string, required" prefetch_priority="int, 1 to 100, required"/>
</prefetch_descriptor>
----
