code: func WrapNetConn(nc net.Conn) net.Conn {
  	if !enabled {
  		return nc
  	}
  	if nc == nil {
  		return nil
  	}
  	return wrappedNetConn{
  		nc,
  		newCloseWrapper(nc),
  	}
  }
docs: // Tracks a net.Conn until Close() is explicitly called.