diff --git a/lib/index.js b/lib/index.js
index <HASH>..<HASH> 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1129,6 +1129,10 @@ class Generator extends EventEmitter {
 
       this._composedWith.forEach(runGenerator);
       this._composedWith = [];
+
+      if (typeof this.env.runLoop.start === 'function') {
+        this.env.runLoop.start();
+      }
     });
 
     // For composed generators, otherwise error will not be catched.
Try to start runLoop manually.

Adds support to run with environment 3.