erlang:decode_packet question

[Max Lapshin]

I cannot understand: it is buf or feature?

erlang:decode_packet(httph_bin, <<"icy-name:Radio Zet\r\n">>, []).
returns me
{more,undefined}

but if I add any useless information in the tail, it works:

erlang:decode_packet(httph_bin, <<"icy-name:Radio Zet\r\nzz">>, []).
{ok,{http_header,0,<<"Icy-Name">>,undefined,<<"Radio Zet">>},
    <<"zz">>}

So to parse headers line by line, I have to artificially append some data.