+// Retrieve the global Executor. If there is none, a default InlineExecutor
+// will be constructed and returned. This is named CPUExecutor to distinguish
+// it from IOExecutor below and to hint that it's intended for CPU-bound tasks.
+std::shared_ptr<Executor> getCPUExecutor();
+
+// Set an Executor to be the global Executor which will be returned by
+// subsequent calls to getCPUExecutor(). Takes a non-owning (weak) reference.
+void setCPUExecutor(std::shared_ptr<Executor> executor);