raft/log.go
func newLogWithSize(storage Storage, logger Logger, maxNextEntsSize uint64) *raftLog {
	if storage == nil {
		log.Panic("storage must not be nil")
	}
	log := &raftLog{
		storage:         storage,
		logger:          logger,
		maxNextEntsSize: maxNextEntsSize,
	}
	firstIndex, err := storage.FirstIndex()
	if err != nil {
		panic(err) // TODO(bdarnell)
	}
	lastIndex, err := storage.LastIndex()
	if err != nil {
		panic(err) // TODO(bdarnell)
	}
	log.unstable.offset = lastIndex + 1
	log.unstable.logger = logger
	// Initialize our committed and applied pointers to the time of the last compaction.
	log.committed = firstIndex - 1
	log.applied = firstIndex - 1

	return log
}
func newLogWithSize(storage Storage, logger Logger, maxNextEntsSize uint64) *raftLog {
	if storage == nil {
		log.Panic("storage must not be nil")
	}
	log := &raftLog{
		storage:         storage,
		logger:          logger,
		maxNextEntsSize: maxNextEntsSize,
	}
	firstIndex, err := storage.FirstIndex()
	if err != nil {
		panic(err) // TODO(bdarnell)
	}
	lastIndex, err := storage.LastIndex()
	if err != nil {
		panic(err) // TODO(bdarnell)
	}
	log.unstable.offset = lastIndex + 1
	log.unstable.logger = logger
	// Initialize our committed and applied pointers to the time of the last compaction.
	log.committed = firstIndex - 1
	log.applied = firstIndex - 1

	return log
}
// newLogWithSize returns a log using the given storage and max
// message size.