slow connection to X server

[Han]

Hi,

I am running X application on remote X server using bluetooth as
transport. I can successfully run the X app  but the start time is
long, e.g. it takes about 7 seconds for "xterm" to appear on the X
server.

I looked at the transport log and it seems there are a large amount of
time at the beginning the X server sending many data (in MBytes) to
the client and the data are most 0, with rare appearance of pattern
similar of "00 00 00 00 02 00 0a 00 0c 00 0a 00 00 00 00 00 01 00 0a".

my question is: in what kind of condition the X server would send
large amount of data to client even before the Window show up?  Is
there any debug tools to decode the data?

Thanks
Han