peer.go
func (l *PeerList) getPeerScore(hostPort string) (*peerScore, uint64, bool) {
	ps, ok := l.peersByHostPort[hostPort]
	if !ok {
		return nil, 0, false
	}
	return ps, ps.score, ok
}
func (l *PeerList) getPeerScore(hostPort string) (*peerScore, uint64, bool) {
	ps, ok := l.peersByHostPort[hostPort]
	if !ok {
		return nil, 0, false
	}
	return ps, ps.score, ok
}
// getPeerScore is called to find the peer and its score from a host port key.
// Note that at least a Read lock must be held to call this function.