arm: cleanup dead async code

arm/async.h

@@ -27,66 +27,6 @@ struct task_final_suspend {
     std::coroutine_handle<> parent;
 };
 
-#if 0
-template <typename T>
-struct gimme {
-    // child interface
-    bool await_ready() { return false; }
-    void await_suspend(std::coroutine_handle<> h) {
-        ha = h;
-        waiting = true;
-        TRACE(tracing::TraceEvent::kAsyncGimmeWaiting);
-
-        if (parent) {
-            TRACE(tracing::TraceEvent::kAsyncCallParent);
-            parent.resume();
-            TRACE(tracing::TraceEvent::kAsyncCallParentDone);
-        }
-    }
-    T await_resume() {
-        waiting = false;
-        TRACE(tracing::TraceEvent::kAsyncGimmeResume);
-        return std::move(stuff);
-    }
-
-    // parent interface
-    auto feed(T&& s) {
-        struct awaitable {
-            bool await_ready() {
-                if (g.waiting) {
-                    return true;
-                }
-                // TODO: handle g.ha.done()
-                return false;
-            }
-            void await_suspend(std::coroutine_handle<> h) {
-                g.parent = h;
-            }
-            void await_resume() {}
-
-            gimme<T>& g;
-        };
-
-        if (!waiting) {
-           __builtin_trap();
-        }
-        if (!ha) {
-           __builtin_trap();
-        }
-        stuff = s;
-        parent = {};
-        ha.resume();
-
-        return awaitable{.g = *this};
-    }
-
-    bool waiting = false;
-    std::coroutine_handle<> ha;
-    T stuff;
-    std::coroutine_handle<> parent;
-};
-#else
-
 template <typename T>
 struct gimme {
     // child interface
@@ -118,7 +58,6 @@ struct gimme {
     std::coroutine_handle<> ha;
     T stuff;
 };
-#endif
 
 template <typename T = void>
 struct task;