Merge remote-tracking branch 'jgras/topic/jgras/event-ts'

* jgras/topic/jgras/event-ts:
  Add compatibility tests for timestamped events.
  Add timestamps to auto published broker events.
  Add timestamps to manually published broker events.
  Annotate scheduled events with intended timestamp.
  Add timestamp to events.

One timestamp to ts rename during the merge.

NEWS

@@ -91,6 +91,19 @@ New Functionality
 
   To disable this functionality, pass ``--disable-javascript`` to configure.
 
+- Zeek events now hold network timestamps. For scheduled events, the timestamp
+  represents the network time for which the event was scheduled for, otherwise
+  it is the network time at event creation. A new bif ``current_event_time()``
+  allows to retrieve the current event's network timestamp within the script-layer.
+
+  When Zeek sends events via Broker to other nodes in a cluster, an event's network
+  timestamp is attached to the Broker messages. On a receiving Zeek node executing a
+  handler for a remote event, ``current_event_time()`` returns the network time of
+  the sending node at the time the event was created.
+
+  The Broker level implementation allows to exchange arbitrary event metadata, but
+  Zeek's script and C++ APIs currently only expose network timestamp functionality.
+
 - A new bif ``from_json()`` can be used to parse JSON strings into records.
 
 	type A: record { a: addr; };