errors: export ErrRecordRetries, ErrRecordTimeout

There's little reason not to export these errors, and they can be useful
for users to know what type of error they're experiencing when
producing.

pkg/kgo/errors.go

@@ -127,16 +127,18 @@ var (
 	// Returned when trying to produce a record outside of a transaction.
 	errNotInTransaction = errors.New("cannot produce record transactionally if not in a transaction")
 
-	// Returned when records are unable to be produced and they hit the
-	// configured record timeout limit.
-	errRecordTimeout = errors.New("records have timed out before they were able to be produced")
-
-	errRecordRetries = errors.New("record failed after being retried too many times")
-
 	//////////////
 	// EXTERNAL //
 	//////////////
 
+	// ErrRecordTimeout is passed to produce promises when records are
+	// unable to be produced within the RecordDeliveryTimeout.
+	ErrRecordTimeout = errors.New("records have timed out before they were able to be produced")
+
+	// ErrRecordRetries is passed to produce promises when records are
+	// unable to be produced after RecordRetries attempts.
+	ErrRecordRetries = errors.New("record failed after being retried too many times")
+
 	// ErrMaxBuffered is returned when producing with manual flushing
 	// enabled and the maximum amount of records are buffered.
 	ErrMaxBuffered = errors.New("manual flushing is enabled and the maximum amount of records are buffered, cannot buffer more")

pkg/kgo/producer.go

@@ -705,7 +705,7 @@ func (cl *Client) waitUnknownTopic(
 		case <-cl.ctx.Done():
 			err = ErrClientClosed
 		case <-after:
-			err = errRecordTimeout
+			err = ErrRecordTimeout
 		case retriableErr, ok := <-unknown.wait:
 			if !ok {
 				cl.cfg.logger.Log(LogLevelInfo, "done waiting for metadata for new topic", "topic", topic)

pkg/kgo/sink.go

@@ -1272,9 +1272,9 @@ func (b *recBatch) maybeFailErr(cfg *cfg) error {
 		}
 	}
 	if b.isTimedOut(cfg.recordTimeout) {
-		return errRecordTimeout
+		return ErrRecordTimeout
 	} else if b.tries >= cfg.recordRetries {
-		return errRecordRetries
+		return ErrRecordRetries
 	} else if b.owner.cl.producer.isAborting() {
 		return ErrAborting
 	}