TailDir should include source file name metadata for sink

When a node use tailDir, and tails for more then one source file, I would like
to recognize the source file name in the sink.

for example:

I have a dir with 3 files in it.
/evia/flume/file1
/evia/flume/file2
/evia/flume/file3

so I want that in the sink all events from file2 will be in a file that have prefix file2.....

Maybe the way to do it is to add the filename as a field of the metadata??

Thanks