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The NL_IN_CHAIN_SET_CLIENT_ATTRIBUTES union defines versioning.

 typedef 
 [switch_type(DWORD)] 
 union {
   [case(1)] 
     NL_IN_CHAIN_SET_CLIENT_ATTRIBUTES_V1 V1;
 } NL_IN_CHAIN_SET_CLIENT_ATTRIBUTES;

V1: An NL_IN_CHAIN_SET_CLIENT_ATTRIBUTES_V1 (section 2.2.1.3.16) structure.<43>