Could someone please elaborate on: dst_speed

[Technology]

file: receive.pm
'0114' => ['skill_use', 'v1 a4 a4 V1 V1 V1 v1 v1 v1 C1', [qw(skillID sourceID targetID tick src_speed dst_speed damage level param3 type)]]

While src_speed seems to be something like an invisible cast before the skill is effectively used, dst_speed remains unknown for me.

When for example i use a skill on someone and miss, the value is 0.
When i hit 1 person multiple times, the value seems to be constant.
So it seems to be bound on other players characters.

Together with this i would want to ask if someone knows how to get the afterskill delay.