SteamKit2.SteamFriends.HandleFriendsList C# (CSharp) Method

        void HandleFriendsList( IPacketMsg packetMsg )
        {
            var list = new ClientMsgProtobuf<CMsgClientFriendsList>( packetMsg );

            cache.LocalUser.SteamID = this.Client.SteamID;

            if ( !list.Body.bincremental )
            {
                // if we're not an incremental update, the message contains all friends, so we should clear our current list
                lock ( listLock )
                {
                    friendList.Clear();
                    clanList.Clear();
                }
            }

            // we have to request information for all of our friends because steam only sends persona information for online friends
            var reqInfo = new ClientMsgProtobuf<CMsgClientRequestFriendData>( EMsg.ClientRequestFriendData );

            reqInfo.Body.persona_state_requested = ( uint )defaultInfoRequest;

            lock ( listLock )
            {
                List<SteamID> friendsToRemove = new List<SteamID>();
                List<SteamID> clansToRemove = new List<SteamID>();

                foreach ( var friendObj in list.Body.friends )
                {
                    SteamID friendId = friendObj.ulfriendid;

                    if ( friendId.IsIndividualAccount )
                    {
                        var user = cache.GetUser( friendId );

                        user.Relationship = ( EFriendRelationship )friendObj.efriendrelationship;

                        if ( friendList.Contains( friendId ) )
                        {
                            // if this is a friend on our list, and they removed us, mark them for removal
                            if ( user.Relationship == EFriendRelationship.None )
                                friendsToRemove.Add( friendId );
                        }
                        else
                        {
                            // we don't know about this friend yet, lets add them
                            friendList.Add( friendId );
                        }

                    }
                    else if ( friendId.IsClanAccount )
                    {
                        var clan = cache.Clans.GetAccount( friendId );

                        clan.Relationship = ( EClanRelationship )friendObj.efriendrelationship;

                        if ( clanList.Contains( friendId ) )
                        {
                            // mark clans we were removed/kicked from
                            // note: not actually sure about the kicked relationship, but i'm using it for good measure
                            if ( clan.Relationship == EClanRelationship.None || clan.Relationship == EClanRelationship.Kicked )
                                clansToRemove.Add( friendId );
                        }
                        else
                        {
                            // don't know about this clan, add it
                            clanList.Add( friendId );
                        }
                    }

                    if ( !list.Body.bincremental )
                    {
                        // request persona state for our friend & clan list when it's a non-incremental update
                        reqInfo.Body.friends.Add( friendId );
                    }
                }

                // remove anything we marked for removal
                friendsToRemove.ForEach( f => friendList.Remove( f ) );
                clansToRemove.ForEach( c => clanList.Remove( c ) );

            }

            if ( reqInfo.Body.friends.Count > 0 )
            {
                this.Client.Send( reqInfo );
            }

#if STATIC_CALLBACKS
            var callback = new FriendsListCallback( Client, list.Body );
            SteamClient.PostCallback( callback );
#else
            var callback = new FriendsListCallback( list.Body );
            this.Client.PostCallback( callback );
#endif
        }
        void HandlePersonaState( IPacketMsg packetMsg )