Use the inner unfiltered Promise's stack as the best stack describing I/O

Author: sebmarkbage

packages/react-server/src/ReactFlightServer.js

@@ -1922,14 +1922,17 @@ function visitAsyncNode(
           // We don't log it yet though. We return it to be logged by the point where it's awaited.
           // The ioNode might be another PromiseNode in the case where none of the AwaitNode had
           // unfiltered stacks.
-          if (
+          if (ioNode.tag === PROMISE_NODE) {
+            // If the ioNode was a Promise, then that means we found one in user space since otherwise
+            // we would've returned an IO node. We assume this has the best stack.
+            match = ioNode;
+          } else if (
             filterStackTrace(request, parseStackTrace(node.stack, 1)).length ===
             0
           ) {
-            // Typically we assume that the outer most Promise that was awaited in user space has the
-            // most actionable stack trace for the start of the operation. However, if this Promise
-            // was created inside only third party code, then try to use the inner node instead.
-            // This could happen if you pass a first party Promise into a third party to be awaited there.
+            // If this Promise was created inside only third party code, then try to use
+            // the inner I/O node instead. This could happen if third party calls into first
+            // party to perform some I/O.
             if (ioNode.end < 0) {
               // If we haven't defined an end time, use the resolve of the outer Promise.
               ioNode.end = node.end;