Remove unused fakeMessage helper methods (#8)

1. Remove unused fakeMessage helper methods (leave and deprecate the
popular zillow one)1
2. Remove unused benchmark
3. Remove zgkafka specific headers (rely on composition root for
enterprise specific headers)

message.go

@@ -3,13 +3,10 @@ package zkafka
 import (
 	"context"
 	"errors"
-	"fmt"
-	"os"
 	"sync"
 	"time"
 
 	"github.com/confluentinc/confluent-kafka-go/v2/kafka"
-	"github.com/google/uuid"
 	"github.com/zillow/zfmt"
 )
 
@@ -32,15 +29,49 @@ type Message struct {
 	doneOnce       sync.Once
 }
 
-// A set of observability headers for ZG Kafka
-const (
-	obsKeyMessageID     = "GUID"
-	obsKeyEventTime     = "eventTime"
-	obsKeyOriginService = "originService"
-	obsKeyOriginHost    = "originHost"
-)
+// DoneWithContext is used to alert that message processing has completed.
+// This marks the message offset to be committed
+func (m *Message) DoneWithContext(ctx context.Context) {
+	m.doneOnce.Do(func() {
+		m.doneFunc(ctx)
+	})
+}
+
+// Done is used to alert that message processing has completed.
+// This marks the message offset to be committed
+func (m *Message) Done() {
+	if m == nil {
+		return
+	}
+	m.doneOnce.Do(func() {
+		m.doneFunc(context.Background())
+	})
+}
+
+// Decode reads message data and stores it in the value pointed to by v.
+func (m *Message) Decode(v any) error {
+	if m.value == nil {
+		return errors.New("message is empty")
+	}
+	if m.fmt == nil {
+		// is error is most likely due to user calling KReader/KWriter
+		// with custom Formatter which can sometimes be nil
+		return errors.New("formatter is not set")
+	}
+	return m.fmt.Unmarshal(m.value, v)
+}
+
+// Value returns a copy of the current value byte array. Useful for debugging
+func (m *Message) Value() []byte {
+	if m == nil || m.value == nil {
+		return nil
+	}
+	out := make([]byte, len(m.value))
+	copy(out, m.value)
+	return out
+}
 
-func makeProducerMessageRaw(_ context.Context, serviceName, topic string, key *string, value []byte) kafka.Message {
+func makeProducerMessageRaw(_ context.Context, topic string, key *string, value []byte) kafka.Message {
 	kafkaMessage := kafka.Message{
 		TopicPartition: kafka.TopicPartition{
 			Topic:     &topic,
@@ -52,26 +83,6 @@ func makeProducerMessageRaw(_ context.Context, serviceName, topic string, key *s
 	if key != nil {
 		kafkaMessage.Key = []byte(*key)
 	}
-	// Observability
-	kafkaMessage.Headers = append(kafkaMessage.Headers, kafka.Header{
-		Key:   obsKeyMessageID,
-		Value: []byte(uuid.New().String()),
-	})
-	kafkaMessage.Headers = append(kafkaMessage.Headers, kafka.Header{
-		Key:   obsKeyEventTime,
-		Value: []byte(fmt.Sprintf("%d", time.Now().Unix())),
-	})
-	kafkaMessage.Headers = append(kafkaMessage.Headers, kafka.Header{
-		Key:   obsKeyOriginService,
-		Value: []byte(serviceName),
-	})
-	//nolint:errcheck // Its not particularly noteworthy if if host isn't propagated forward. We'll suppress the error
-	hostname, _ := os.Hostname()
-	// hn is empty string if there's an error
-	kafkaMessage.Headers = append(kafkaMessage.Headers, kafka.Header{
-		Key:   obsKeyOriginHost,
-		Value: []byte(hostname),
-	})
 	return kafkaMessage
 }
 
@@ -103,48 +114,6 @@ func headers(msg kafka.Message) map[string][]byte {
 	return res
 }
 
-// DoneWithContext is used to alert that message processing has completed.
-// This marks the message offset to be committed
-func (m *Message) DoneWithContext(ctx context.Context) {
-	m.doneOnce.Do(func() {
-		m.doneFunc(ctx)
-	})
-}
-
-// Done is used to alert that message processing has completed.
-// This marks the message offset to be committed
-func (m *Message) Done() {
-	if m == nil {
-		return
-	}
-	m.doneOnce.Do(func() {
-		m.doneFunc(context.Background())
-	})
-}
-
-// Decode reads message data and stores it in the value pointed to by v.
-func (m *Message) Decode(v any) error {
-	if m.value == nil {
-		return errors.New("message is empty")
-	}
-	if m.fmt == nil {
-		// is error is most likely due to user calling KReader/KWriter
-		// with custom Formatter which can sometimes be nil
-		return errors.New("formatter is not set")
-	}
-	return m.fmt.Unmarshal(m.value, v)
-}
-
-// Value returns a copy of the current value byte array. Useful for debugging
-func (m *Message) Value() []byte {
-	if m == nil || m.value == nil {
-		return nil
-	}
-	out := make([]byte, len(m.value))
-	copy(out, m.value)
-	return out
-}
-
 // Response is a kafka response with the Partition where message was sent to along with its assigned Offset
 type Response struct {
 	Partition int32

message_test.go

@@ -41,13 +41,13 @@ func Test_makeProducerMessageRaw(t *testing.T) {
 				Opaque:  nil,
 				Headers: nil,
 			},
-			hasHeaders: true,
+			hasHeaders: false,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			defer recoverThenFail(t)
-			got := makeProducerMessageRaw(tt.args.ctx, tt.args.serviceName, tt.args.topic, tt.args.key, tt.args.value)
+			got := makeProducerMessageRaw(tt.args.ctx, tt.args.topic, tt.args.key, tt.args.value)
 			require.Equal(t, tt.want.TopicPartition, got.TopicPartition)
 			require.Equal(t, tt.want.Key, got.Key)
 			require.Equal(t, tt.want.Key, got.Key)