One can’t easily compose two existing BodyProcessors, even if they know what
bytes should be dispatched to each BodyProcessor. Example use cases (don’t
know whether or not they are common):

  - Read image header, then dispatch the image body to a file.

  - Decode a .zip file, dispatching each entry to a separate BodyProcessor.

  - Applications seem to be forced to implement BodyHandler even if they want
    to accept all response bodies (⇨ SimpleBodyHandler)?


This issue has been filed to capture comments raised by tobiast at google dot com, see
http://mail.openjdk.java.net/pipermail/net-dev/2017-July/010872.html