Logging Connection termination reason

[Georg]

 Hi,

i do have problems with some clients downloading a adobe flex rsl file
(application/x-swz) - I see a lot of requests with different/invalid
$body_bytes_sent values - however the file in the zone cache directory
is expected to be always the same size.

To isolate the probelm i would need to debug the termination reason -
this could be - a client aborted the download (timeout, connection reset
by peer, whatever) or the connection was terminated regular (eof).

The only option i have found so far is running the error_log in
debug_http mode - which causes the webserver to suffer due to the amount
of diskio.

Is there a way to log which side has terminated the connection or the
reason for terminating the connection ?
Is there a way to have error_log mode for a specific url ?

regards
Georg