franz-go: fix 32 bit alignment, fix a few lints

Committing this before the next bigger lint-fixing commit

This commit moves a few atomics to the top of structs, ensuring
alignment. This was caught with the new github actions, which is a bit
slow.

examples/requesting/request_metadata.go

@@ -1,4 +1,4 @@
-package requesting
+package main
 
 import (
 	"context"
@@ -12,7 +12,7 @@ import (
 	"github.com/twmb/franz-go/pkg/kversion"
 )
 
-func requestMetadata() {
+func main() {
 	seeds := []string{"localhost:9092"}
 	client, err := kgo.NewClient(
 		kgo.SeedBrokers(seeds...),

generate/main.go

@@ -79,6 +79,7 @@ type (
 	// The following types can be encoded "compact"; this happens on
 	// flexible versions. If adding types here, be sure to add the
 	// AsFromFlexible method below.
+
 	String struct {
 		FromFlexible bool
 	}

pkg/kgo/broker.go

@@ -589,6 +589,8 @@ func (b *broker) connect(ctx context.Context) (net.Conn, error) {
 // brokerCxn manages an actual connection to a Kafka broker. This is separate
 // the broker struct to allow lazy connection (re)creation.
 type brokerCxn struct {
+	throttleUntil int64 // atomic nanosec
+
 	conn net.Conn
 
 	cl *Client
@@ -599,8 +601,6 @@ type brokerCxn struct {
 	mechanism sasl.Mechanism
 	expiry    time.Time
 
-	throttleUntil int64 // atomic nanosec
-
 	corrID int32
 
 	// The following four fields are used for connection reaping.

pkg/kgo/consumer.go

@@ -153,10 +153,10 @@ func (o Offset) At(at int64) Offset {
 }
 
 type consumer struct {
-	cl *Client
-
 	bufferedRecords int64
 
+	cl *Client
+
 	pausedMu sync.Mutex   // grabbed when updating paused
 	paused   atomic.Value // loaded when issuing fetches
 

pkg/kgo/group_balancer.go

@@ -110,7 +110,7 @@ func (*ConsumerBalancer) Balance(map[string]int32) IntoSyncAssignment {
 	panic("unreachable")
 }
 
-// Balance satisfies the GroupMemberBalancerOrError interface.
+// BalanceOrError satisfies the GroupMemberBalancerOrError interface.
 func (b *ConsumerBalancer) BalanceOrError(topics map[string]int32) (IntoSyncAssignment, error) {
 	return b.b.Balance(b, topics), b.err
 }

pkg/kgo/producer.go

@@ -14,6 +14,9 @@ import (
 )
 
 type producer struct {
+	bufferedRecords int64
+	inflight        int64 // high 16: # waiters, low 48: # inflight
+
 	cl *Client
 
 	topicsMu sync.Mutex // locked to prevent concurrent updates; reads are always atomic
@@ -34,8 +37,6 @@ type producer struct {
 	unknownTopicsMu sync.Mutex
 	unknownTopics   map[string]*unknownTopicProduces
 
-	bufferedRecords int64
-
 	id           atomic.Value
 	producingTxn uint32 // 1 if in txn
 
@@ -55,8 +56,6 @@ type producer struct {
 	mu sync.Mutex
 	c  *sync.Cond
 
-	inflight int64 // high 16: # waiters, low 48: # inflight
-
 	batchPromises ringBatchPromise
 	promisesMu    sync.Mutex
 
@@ -484,7 +483,7 @@ func (cl *Client) finishRecordPromise(pr promisedRec, err error) {
 		p.waitBuffer <- struct{}{}
 	} else if buffered == 0 && atomic.LoadInt32(&p.flushing) > 0 {
 		p.mu.Lock()
-		p.mu.Unlock() // nolint:gocritic,staticcheck // We use the lock as a barrier, unlocking immediately is safe.
+		p.mu.Unlock() //nolint:gocritic,staticcheck // We use the lock as a barrier, unlocking immediately is safe.
 		p.c.Broadcast()
 	}
 }

pkg/kgo/record_formatter.go

@@ -26,8 +26,8 @@ import (
 
 // RecordFormatter formats records.
 type RecordFormatter struct {
-	fns   []func([]byte, *FetchPartition, *Record) []byte
 	calls int64
+	fns   []func([]byte, *FetchPartition, *Record) []byte
 }
 
 // AppendRecord appends a record to b given the parsed format and returns the