[libmicrohttpd] MHD_ContentReaderCallback empty content

[Sascha Swiercy]

I'd like to know if it is possible to use
MHD_create_response_from_callback even if the content length is 0. I
tried to pass 0 as first argument to MHD_create_response_from_callback
and also returned 0 from the callback, but this made the library to
invoke the callback function in an infinite loop. The documentation
also states this behavior, but I was curious if there is a way to use
MHD_create_response_from_callback even for an empty response body. If
not, then I'd suggest to make MHD_create_response_from_callback fail
in some way if 0 is passed as size. Thanks for your help.

-Sascha