Unistore: Batch write events (#101381)

* Batch write events

* Improve instrumentation

* Measure batch phases

* Detect lock contention

* remove the execBatch goroutine

* removing tracing prefix

* detect context cancel

* batch channel map

pkg/storage/unified/sql/bulk.go

@@ -245,7 +245,9 @@ func (b *backend) processBulk(ctx context.Context, setting resource.BulkSettings
 			}
 
 			// Make sure the collection RV is above our last written event
-			_, err = b.resourceVersionAtomicInc(ctx, tx, key)
+			_, err = b.rvManager.ExecWithRV(ctx, key, func(tx db.Tx) (string, error) {
+				return "", nil
+			})
 			if err != nil {
 				b.log.Warn("error increasing RV", "error", err)
 			}