diff --git a/vendor/github.com/bsm/sarama-cluster/balancer.go b/vendor/github.com/bsm/sarama-cluster/balancer.go
new file mode 100644
index 0000000..3aeaece
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/balancer.go
@@ -0,0 +1,170 @@
+package cluster
+
+import (
+	"math"
+	"sort"
+
+	"github.com/Shopify/sarama"
+)
+
+// NotificationType defines the type of notification
+type NotificationType uint8
+
+// String describes the notification type
+func (t NotificationType) String() string {
+	switch t {
+	case RebalanceStart:
+		return "rebalance start"
+	case RebalanceOK:
+		return "rebalance OK"
+	case RebalanceError:
+		return "rebalance error"
+	}
+	return "unknown"
+}
+
+const (
+	UnknownNotification NotificationType = iota
+	RebalanceStart
+	RebalanceOK
+	RebalanceError
+)
+
+// Notification are state events emitted by the consumers on rebalance
+type Notification struct {
+	// Type exposes the notification type
+	Type NotificationType
+
+	// Claimed contains topic/partitions that were claimed by this rebalance cycle
+	Claimed map[string][]int32
+
+	// Released contains topic/partitions that were released as part of this rebalance cycle
+	Released map[string][]int32
+
+	// Current are topic/partitions that are currently claimed to the consumer
+	Current map[string][]int32
+}
+
+func newNotification(current map[string][]int32) *Notification {
+	return &Notification{
+		Type:    RebalanceStart,
+		Current: current,
+	}
+}
+
+func (n *Notification) success(current map[string][]int32) *Notification {
+	o := &Notification{
+		Type:     RebalanceOK,
+		Claimed:  make(map[string][]int32),
+		Released: make(map[string][]int32),
+		Current:  current,
+	}
+	for topic, partitions := range current {
+		o.Claimed[topic] = int32Slice(partitions).Diff(int32Slice(n.Current[topic]))
+	}
+	for topic, partitions := range n.Current {
+		o.Released[topic] = int32Slice(partitions).Diff(int32Slice(current[topic]))
+	}
+	return o
+}
+
+// --------------------------------------------------------------------
+
+type topicInfo struct {
+	Partitions []int32
+	MemberIDs  []string
+}
+
+func (info topicInfo) Perform(s Strategy) map[string][]int32 {
+	if s == StrategyRoundRobin {
+		return info.RoundRobin()
+	}
+	return info.Ranges()
+}
+
+func (info topicInfo) Ranges() map[string][]int32 {
+	sort.Strings(info.MemberIDs)
+
+	mlen := len(info.MemberIDs)
+	plen := len(info.Partitions)
+	res := make(map[string][]int32, mlen)
+
+	for pos, memberID := range info.MemberIDs {
+		n, i := float64(plen)/float64(mlen), float64(pos)
+		min := int(math.Floor(i*n + 0.5))
+		max := int(math.Floor((i+1)*n + 0.5))
+		sub := info.Partitions[min:max]
+		if len(sub) > 0 {
+			res[memberID] = sub
+		}
+	}
+	return res
+}
+
+func (info topicInfo) RoundRobin() map[string][]int32 {
+	sort.Strings(info.MemberIDs)
+
+	mlen := len(info.MemberIDs)
+	res := make(map[string][]int32, mlen)
+	for i, pnum := range info.Partitions {
+		memberID := info.MemberIDs[i%mlen]
+		res[memberID] = append(res[memberID], pnum)
+	}
+	return res
+}
+
+// --------------------------------------------------------------------
+
+type balancer struct {
+	client sarama.Client
+	topics map[string]topicInfo
+}
+
+func newBalancerFromMeta(client sarama.Client, members map[string]sarama.ConsumerGroupMemberMetadata) (*balancer, error) {
+	balancer := newBalancer(client)
+	for memberID, meta := range members {
+		for _, topic := range meta.Topics {
+			if err := balancer.Topic(topic, memberID); err != nil {
+				return nil, err
+			}
+		}
+	}
+	return balancer, nil
+}
+
+func newBalancer(client sarama.Client) *balancer {
+	return &balancer{
+		client: client,
+		topics: make(map[string]topicInfo),
+	}
+}
+
+func (r *balancer) Topic(name string, memberID string) error {
+	topic, ok := r.topics[name]
+	if !ok {
+		nums, err := r.client.Partitions(name)
+		if err != nil {
+			return err
+		}
+		topic = topicInfo{
+			Partitions: nums,
+			MemberIDs:  make([]string, 0, 1),
+		}
+	}
+	topic.MemberIDs = append(topic.MemberIDs, memberID)
+	r.topics[name] = topic
+	return nil
+}
+
+func (r *balancer) Perform(s Strategy) map[string]map[string][]int32 {
+	res := make(map[string]map[string][]int32, 1)
+	for topic, info := range r.topics {
+		for memberID, partitions := range info.Perform(s) {
+			if _, ok := res[memberID]; !ok {
+				res[memberID] = make(map[string][]int32, 1)
+			}
+			res[memberID][topic] = partitions
+		}
+	}
+	return res
+}