Add support for concatenated modules

Author: gaearon

packages/react-server-dom-webpack/src/ReactFlightWebpackPlugin.js

@@ -197,6 +197,12 @@ export default class ReactFlightWebpackPlugin {
         chunkGroup.chunks.forEach(chunk => {
           chunk.getModules().forEach(mod => {
             recordModule(mod.id, mod);
+            // If this is a concatenation, register each child to the parent ID.
+            if (mod.modules) {
+              mod.modules.forEach(concatenatedMod => {
+                recordModule(mod.id, concatenatedMod);
+              });
+            }
           });
         });
       });