[FFmpeg-user] how ffmpeg send video data to ffserver

[Soho Soho123]

Hi All,

the command line I use:
ffmpeg -f video4linux2 -r 30 -s 640x480 -input_format mjpeg -i /dev/video0
-vcodec copy http://localhost:8090/feed1.ffm

after trace ffmpeg code, I see in do_streamcopy(),
do_streamcopy() will call write_frame(), and next
write_frame() will call av_interleaved_write_frame(),

I do not see the code about socket write.
Because I see ffserver will keep receive data from socket.
Does anyone have idea about this question?

where is the code that help ffmpeg to send data to ffserver?