curl(1) -N
transfer a URL
-N, --no-buffer
       Disables the buffering of the output stream. In normal work situations, curl will use  a  standard
       buffered  output  stream  that  will  have  the effect that it will output the data in chunks, not
       necessarily exactly when the data arrives.  Using this option will disable that buffering.

       Note that this is the negated option name documented. You can thus use  --buffer  to  enforce  the
source manpages: curl