Fluentd Icecast input with request line split

gistfile1.txt

Regex: 
^(?<host>[^ ]*) (?<logname>[^ ]*) (?<user>[^ ]*) \[(?<time>[^\]]*)\] \"GET (?<request_uri>[^\?]+)\?(?<request_args>[^ ]*) (?<request_protocol>[^ ]*)\" (?<response>[^ ]*) (?<bytes>[^ ]*) \"(?<referrer>[^\"]*)\" \"(?<agent>[^\"]*)\" (?<duration>[^ ]*)

Time Format:
%d/%b/%Y:%H:%M:%S %z

fluent.conf
<source> 
  type tail 
  path /var/log/foo/bar.log 
  pos_file /var/log/td-agent/foo-bar.log.pos 
  tag foo.bar 
  format /^(?<host>[^ ]*) (?<logname>[^ ]*) (?<user>[^ ]*) \[(?<time>[^\]]*)\] \"GET (?<request_uri>[^\?]+)\?(?<request_args>[^ ]*) (?<request_protocol>[^ ]*)\" (?<response>[^ ]*) (?<bytes>[^ ]*) \"(?<referrer>[^\"]*)\" \"(?<agent>[^\"]*)\" (?<duration>[^ ]*)/ 
  time_format %d/%b/%Y:%H:%M:%S %z 
</source>