The result's bHit property determines whether the mouse wheel action will be captured. (Perhaps the mouse wheel only does something when mousing over some part of a mesh)
OnMouseWheelScrollUp
CurrentPos device position/ray at point where mouse wheel is engaged
OnMouseWheelScrollDown
CurrentPos device position/ray at point where mouse wheel is engaged
CaptureCheck
Only enable capture if returns true
CapturePriority
The priority is used to resolve situations where multiple behaviors want the same capture