Add more logging in the batch queue

op-node/rollup/derive/batch_queue.go

@@ -221,6 +221,10 @@ batchLoop:
 	expiryEpoch := epoch.Number + bq.config.SeqWindowSize
 	forceEmptyBatches := (expiryEpoch == bq.origin.Number && outOfData) || expiryEpoch < bq.origin.Number
 
+	bq.log.Trace("Potentially generating an empty batch",
+		"expiryEpoch", expiryEpoch, "forceEmptyBatches", forceEmptyBatches, "nextTimestamp", nextTimestamp,
+		"epoch_time", epoch.Time, "len_l1_blocks", len(bq.l1Blocks))
+
 	if !forceEmptyBatches {
 		// sequence window did not expire yet, still room to receive batches for the current epoch,
 		// no need to force-create empty batch(es) towards the next epoch yet.
@@ -235,6 +239,7 @@ batchLoop:
 	// Fill with empty L2 blocks of the same epoch until we meet the time of the next L1 origin,
 	// to preserve that L2 time >= L1 time
 	if nextTimestamp < nextEpoch.Time {
+		bq.log.Trace("Generating next batch", "epoch", epoch, "timestamp", nextTimestamp)
 		return &BatchData{
 			BatchV1{
 				ParentHash:   l2SafeHead.Hash,
@@ -248,6 +253,7 @@ batchLoop:
 
 	// At this point we have auto generated every batch for the current epoch
 	// that we can, so we can advance to the next epoch.
+	bq.log.Trace("Advancing internal L1 blocks", "next_timestamp", nextTimestamp, "next_epoch_time", nextEpoch.Time)
 	bq.l1Blocks = bq.l1Blocks[1:]
 	return nil, io.EOF
 }