def add_tracker(wfid, action, tracker_id, conditions, msg)

      @context.tracker.add_tracker(wfid, action, tracker_id, conditions, msg)
    end
def add_tracker(wfid, action, tracker_id, conditions, msg)

      @context.tracker.add_tracker(wfid, action, tracker_id, conditions, msg)
    end
/!\ warning: advanced method.

 Adds a tracker to the ruote engine.

 === Arguments

 * wfid:
   When nil will track any workflow execution, when set will only
   react on msgs for the given wfid.
 * action:
   A string like "apply", "reply" or "receive", the action being tracked
   May begin with a "pre_" prefix.
 * tracker_id:
   When nil, ruote chooses a tracker_id, else its the unique identifier
   for the new tracker.
 * conditions:
   A Hash of keys pointing to arrays of expected values.
   For example { 'tree.0' ~=> [ 'alfred', 'knuth' ] } will trigger
   if the first element of msg['tree'] equals alfred or knuth.
 * msg:
   The msg to place in the msg queue if the tracker matches the msg,
   the reaction.

 Returns the tracker_id.