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Doc comment changes, metrics naming, and queue length.
For reasoning behind chosen queue length, see #6747 (comment)

Co-authored-by: Jordan Schalm <[email protected]>

Author: tim-barry

engine/collection/pusher/engine.go

@@ -25,8 +25,9 @@ import (
 	"github.com/onflow/flow-go/utils/logging"
 )
 
-// Engine is part of the Collection Nodes. It broadcasts finalized collections
-// that the cluster generates to the broader network.
+// Engine is part of the Collection Node. It broadcasts finalized collections
+// ("collection guarantees") that the cluster generates to Consensus Nodes
+// for inclusion in blocks.
 type Engine struct {
 	log          zerolog.Logger
 	engMetrics   module.EngineMetrics
@@ -61,7 +62,7 @@ func New(
 	transactions storage.Transactions,
 ) (*Engine, error) {
 	queue, err := fifoqueue.NewFifoQueue(
-		1000,
+		200, // roughly 1 minute of collections, at 3BPS
 		fifoqueue.WithLengthObserver(func(len int) {
 			mempoolMetrics.MempoolEntries(metrics.ResourceSubmitCollectionGuaranteesQueue, uint(len))
 		}),
@@ -99,7 +100,8 @@ func New(
 	return e, nil
 }
 
-// Worker to process SubmitCollectionGuarantee messages coming from the Finalizer.
+// outboundQueueWorker implements a component worker which broadcasts collection guarantees, 
+// enqueued by the Finalizer upon finalization, to Consensus Nodes.
 func (e *Engine) outboundQueueWorker(ctx irrecoverable.SignalerContext, ready component.ReadyFunc) {
 	ready()
 

module/metrics/labels.go

@@ -113,7 +113,7 @@ const (
 	ResourceFollowerLoopCertifiedBlocksChannel    = "follower_loop_certified_blocks_channel"    // follower loop, certified blocks buffered channel
 	ResourceClusterBlockProposalQueue             = "cluster_compliance_proposal_queue"         // collection node, compliance engine
 	ResourceTransactionIngestQueue                = "ingest_transaction_queue"                  // collection node, ingest engine
-	ResourceSubmitCollectionGuaranteesQueue       = "submit_col_guarantee_queue"                // collection node, pusher engine
+	ResourceSubmitCollectionGuaranteesQueue       = "pusher_col_guarantee_queue"                // collection node, pusher engine
 	ResourceBeaconKey                             = "beacon-key"                                // consensus node, DKG engine
 	ResourceDKGMessage                            = "dkg_private_message"                       // consensus, DKG messaging engine
 	ResourceApprovalQueue                         = "sealing_approval_queue"                    // consensus node, sealing engine