Shift fetching litho attributes to background thread

Summary: Due to litho component instances being immutable we are able to process them later if we hold on to the instance. We have added a Maybe deferred type which sort of resembles a Monad. It wraps a value which may or may not be calculated later.

Reviewed By: lblasa

Differential Revision: D41474251

fbshipit-source-id: 2ba6e688518dba55cf4aa5ba53f390a92cf0921f

desktop/plugins/public/ui-debugger/components/PerfStats.tsx

@@ -63,11 +63,21 @@ const columns: DataTableColumn<PerfStatsEvent>[] = [
       return formatDiff(row.snapshotComplete, row.queuingComplete);
     },
   },
+  {
+    key: 'deferredComputationComplete',
+    title: 'Deferred processing time',
+    onRender: (row: PerfStatsEvent) => {
+      return formatDiff(row.queuingComplete, row.deferredComputationComplete);
+    },
+  },
   {
     key: 'serializationComplete',
     title: 'Serialization time',
     onRender: (row: PerfStatsEvent) => {
-      return formatDiff(row.queuingComplete, row.serializationComplete);
+      return formatDiff(
+        row.deferredComputationComplete,
+        row.serializationComplete,
+      );
     },
   },
   {