func (l *raftLog) hasNextEnts() bool {
	off := max(l.applied+1, l.firstIndex())
	return l.committed+1 > off
}
func (l *raftLog) hasNextEnts() bool {
	off := max(l.applied+1, l.firstIndex())
	return l.committed+1 > off
}
// hasNextEnts returns if there is any available entries for execution. This
// is a fast check without heavy raftLog.slice() in raftLog.nextEnts().