Need Clarification on VLC Sout Statistics

[GEFORCEXTREME]

Hi, when a VLC is used as a video stream server, there are 2 statistics. They are,

1) sending bitrate
2) sent bytes

My question is, how fast/rapidly does VLC stream out packetised data? Does VLC do it as fast as possible as given by the available bandwidth of the connection (available bandwidth dependant), or does VLC send as fast as it is able to process (and/or transcode) and then packetised the data (CPU resource dependant), or is it a mixture of both, or is it something else?

Someone please give me inside on this. Thank you.