title: Using NiFi Flowfiles as an Event Notifier
body: <p>New to NiFi!</p>
  
  <p>I was wondering if there is a way to send an empty flowfile with attributes on the flowfile in NiFi? I'd like to use this as a trigger to indicate that a type of event has Started.</p>
  
  <p>In NiFi is there any other way for me to indicate that a set of events have started and finished? For instance, if i have three processors that read in data and i would like to know that the first processor is about to be triggered and that the last processor has finished. Is there anyway for me to do this? If the processors continue to run, i would like to be able to group the data read from processor 1 to processor 3 in one pass. To make this more clear</p>
  
  <pre><code>Begin
  Processor1
  Processor2
  Processor3
  End
  Begin
  Processor1
  Processor2
  Processor3
  End
  ...
  </code></pre>
  
  <p>Any help would be appreciated,
  Thanks in advance!</p>