diff --git a/vendor/github.com/Shopify/sarama/prep_encoder.go b/vendor/github.com/Shopify/sarama/prep_encoder.go
new file mode 100644
index 0000000..b633cd1
--- /dev/null
+++ b/vendor/github.com/Shopify/sarama/prep_encoder.go
@@ -0,0 +1,153 @@
+package sarama
+
+import (
+	"encoding/binary"
+	"fmt"
+	"math"
+
+	"github.com/rcrowley/go-metrics"
+)
+
+type prepEncoder struct {
+	stack  []pushEncoder
+	length int
+}
+
+// primitives
+
+func (pe *prepEncoder) putInt8(in int8) {
+	pe.length++
+}
+
+func (pe *prepEncoder) putInt16(in int16) {
+	pe.length += 2
+}
+
+func (pe *prepEncoder) putInt32(in int32) {
+	pe.length += 4
+}
+
+func (pe *prepEncoder) putInt64(in int64) {
+	pe.length += 8
+}
+
+func (pe *prepEncoder) putVarint(in int64) {
+	var buf [binary.MaxVarintLen64]byte
+	pe.length += binary.PutVarint(buf[:], in)
+}
+
+func (pe *prepEncoder) putArrayLength(in int) error {
+	if in > math.MaxInt32 {
+		return PacketEncodingError{fmt.Sprintf("array too long (%d)", in)}
+	}
+	pe.length += 4
+	return nil
+}
+
+func (pe *prepEncoder) putBool(in bool) {
+	pe.length++
+}
+
+// arrays
+
+func (pe *prepEncoder) putBytes(in []byte) error {
+	pe.length += 4
+	if in == nil {
+		return nil
+	}
+	return pe.putRawBytes(in)
+}
+
+func (pe *prepEncoder) putVarintBytes(in []byte) error {
+	if in == nil {
+		pe.putVarint(-1)
+		return nil
+	}
+	pe.putVarint(int64(len(in)))
+	return pe.putRawBytes(in)
+}
+
+func (pe *prepEncoder) putRawBytes(in []byte) error {
+	if len(in) > math.MaxInt32 {
+		return PacketEncodingError{fmt.Sprintf("byteslice too long (%d)", len(in))}
+	}
+	pe.length += len(in)
+	return nil
+}
+
+func (pe *prepEncoder) putNullableString(in *string) error {
+	if in == nil {
+		pe.length += 2
+		return nil
+	}
+	return pe.putString(*in)
+}
+
+func (pe *prepEncoder) putString(in string) error {
+	pe.length += 2
+	if len(in) > math.MaxInt16 {
+		return PacketEncodingError{fmt.Sprintf("string too long (%d)", len(in))}
+	}
+	pe.length += len(in)
+	return nil
+}
+
+func (pe *prepEncoder) putStringArray(in []string) error {
+	err := pe.putArrayLength(len(in))
+	if err != nil {
+		return err
+	}
+
+	for _, str := range in {
+		if err := pe.putString(str); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (pe *prepEncoder) putInt32Array(in []int32) error {
+	err := pe.putArrayLength(len(in))
+	if err != nil {
+		return err
+	}
+	pe.length += 4 * len(in)
+	return nil
+}
+
+func (pe *prepEncoder) putInt64Array(in []int64) error {
+	err := pe.putArrayLength(len(in))
+	if err != nil {
+		return err
+	}
+	pe.length += 8 * len(in)
+	return nil
+}
+
+func (pe *prepEncoder) offset() int {
+	return pe.length
+}
+
+// stackable
+
+func (pe *prepEncoder) push(in pushEncoder) {
+	in.saveOffset(pe.length)
+	pe.length += in.reserveLength()
+	pe.stack = append(pe.stack, in)
+}
+
+func (pe *prepEncoder) pop() error {
+	in := pe.stack[len(pe.stack)-1]
+	pe.stack = pe.stack[:len(pe.stack)-1]
+	if dpe, ok := in.(dynamicPushEncoder); ok {
+		pe.length += dpe.adjustLength(pe.length)
+	}
+
+	return nil
+}
+
+// we do not record metrics during the prep encoder pass
+func (pe *prepEncoder) metricRegistry() metrics.Registry {
+	return nil
+}