Godeps/_workspace/src/gopkg.in/mgo.v2/session.go
func (s *Session) setSocket(socket *mongoSocket) {
	info := socket.Acquire()
	if info.Master {
		if s.masterSocket != nil {
			panic("setSocket(master) with existing master socket reserved")
		}
		s.masterSocket = socket
	} else {
		if s.slaveSocket != nil {
			panic("setSocket(slave) with existing slave socket reserved")
		}
		s.slaveSocket = socket
	}
}
func (s *Session) setSocket(socket *mongoSocket) {
	info := socket.Acquire()
	if info.Master {
		if s.masterSocket != nil {
			panic("setSocket(master) with existing master socket reserved")
		}
		s.masterSocket = socket
	} else {
		if s.slaveSocket != nil {
			panic("setSocket(slave) with existing slave socket reserved")
		}
		s.slaveSocket = socket
	}
}
// setSocket binds socket to this section.