Github user davemssavage commented on the issue:
https://github.com/apache/nifi/pull/3068
Great, I was thinking it would make sense to support all the types that
MergeContent supports, however I didn't want to go down that route till others
had a chance to comment on the options. I'll take a look at the other formats
and submit an update soon with an updated description and more input format
options---
