Fix up async wrappers. Comment out gevent stuff for now

capnp/asyncHelper.h

@@ -3,6 +3,9 @@
 
 extern "C" {
    PyObject * wrap_kj_exception(kj::Exception &);
+   // void _gevent_eventloop_prepare_to_sleep();
+   // void _gevent_eventloop_sleep();
+   // void _gevent_eventloop_wake();
 }
 
 PyObject * wrapPyFunc(PyObject * func, PyObject * arg) {
@@ -21,4 +24,32 @@ PyObject * wrapPyFunc(PyObject * func, PyObject * arg) {
   else
     return loop.there(kj::mv(promise), [func](PyObject * arg) { return wrapPyFunc(func, arg); } 
                                      , [error_func](kj::Exception arg) { return wrapPyFunc(error_func, wrap_kj_exception(arg)); } );
-}
+}
+::kj::Promise<PyObject *> then(kj::Promise<PyObject *> & promise, PyObject * func, PyObject * error_func) {
+  if(error_func == Py_None)
+    return promise.then([func](PyObject * arg) { return wrapPyFunc(func, arg); } );
+  else
+    return promise.then([func](PyObject * arg) { return wrapPyFunc(func, arg); } 
+                                     , [error_func](kj::Exception arg) { return wrapPyFunc(error_func, wrap_kj_exception(arg)); } );
+}
+
+::kj::Promise<PyObject *> yield_end(kj::EventLoop & loop) {
+  return loop.there(loop.yield(), []() { Py_RETURN_NONE; } );
+}
+
+// class PyEventLoop final: public ::kj::EventLoop {
+// public:
+//   PyEventLoop() {}
+//   ~PyEventLoop() noexcept(false) {}
+
+// protected:
+//   void prepareToSleep() noexcept override {
+//     _gevent_eventloop_prepare_to_sleep();
+//   }
+//   void sleep() override {
+//     _gevent_eventloop_sleep();
+//   }
+//   void wake() const override {
+//     _gevent_eventloop_wake();
+//   }
+// };