The trickling way is what I need, unfortunately it looks like there is no way of sending the response in pieces, because the code reference refers to a HTTP::Response object, that is evaluated before sending. This is the interesting part from HTTP::Daemon, line 445

sub send_response
{
    my $self = shift;
    my $res = shift;
    if (!ref $res) {
    $res ||= RC_OK;
    $res = HTTP::Response->new($res, @_);
    }
    my $content = $res->content;
...
[download]