Public Overridable Function onQueryEventAttributes( _
   ByVal eventCategory As Integer, _
   ByRef count As Integer, _
   ByRef attrIDs As Integer(), _
   ByRef attrDescs As String(), _
   ByRef attrTypes As Type() _
) As Integer

public virtual int onQueryEventAttributes( 
   int eventCategory,
   out int count,
   out int[] attrIDs,
   out string[] attrDescs,
   out Type[] attrTypes
)